Advances in Meteorology http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Standardized Water Budget Index and Validation in Drought Estimation of Haihe River Basin, North China Tue, 28 Jun 2016 15:42:49 +0000 http://www.hindawi.com/journals/amete/2016/9159532/ The physical-based drought indices such as the self-calibrated Palmer Drought Severity Index (sc-PDSI) with the fixed time scale is inadequate for the multiscalar drought assessment, and the multiscalar drought indices including Standardized Precipitation Index (SPI), Reconnaissance Drought Index (RDI), and Standardized Precipitation Evapotranspiration Index (SPEI) based on the meteorological factors are lack of physical mechanism and cannot depict the actual water budget. To fill this gap, the Standardized Water Budget Index (SWBI) is constructed based on the difference between areal precipitation and actual evapotranspiration (AET), which can describe the actual water budget but also assess the drought at multiple time scales. Then, sc-PDSI was taken as the reference drought index to compare with multiscalar drought indices at different time scale in Haihe River basin. The result shows that SWBI correlates better with sc-PDSI and the RMSE of SWBI is less than other multiscalar drought indices. In addition, all of drought indices show a decreasing trend in Haihe River Basin, possibly due to the decreasing precipitation from 1961 to 2010. The decreasing trends of SWBI were significant and consistent at all the time scales, while the decreasing trends of other multiscalar drought indices are insignificant at time scale less than 3 months. Shaohua Liu, Denghua Yan, Hao Wang, Chuanzhe Li, Baisha Weng, and Tianling Qin Copyright © 2016 Shaohua Liu et al. All rights reserved. Advances in Remote Sensing and Modeling of Terrestrial Hydrometeorological Processes and Extremes Mon, 27 Jun 2016 09:05:39 +0000 http://www.hindawi.com/journals/amete/2016/4371840/ Ke Zhang, Jingfeng Wang, Iftekhar Ahmed, and Prasanna H. Gowda Copyright © 2016 Ke Zhang et al. All rights reserved. Detecting Variation Trends of Temperature and Precipitation for the Dadu River Basin, China Thu, 23 Jun 2016 12:12:30 +0000 http://www.hindawi.com/journals/amete/2016/2564586/ This study analyzes the variation trends of temperature and precipitation in the Dadu River Basin of China based on observed records from fourteen meteorological stations. The magnitude of trends was estimated using Sen’s linear method while its statistical significance was evaluated using Mann-Kendall’s test. The results of analysis depict increase change from northwest to southeast of annual temperature and precipitation in space. In temporal scale, the annual temperature showed significant increase trend and the annual precipitation showed increase trend. For extreme indices, the trends for temperature are more consistent in the region compared to precipitation. This paper has practical meanings for an effective management of climate risk and provides a foundation for further study of hydrological situation in this river basin. Ying Wu, Wensheng Wang, and Guoqing Wang Copyright © 2016 Ying Wu et al. All rights reserved. Heat-Wave Events in Spain: Air Mass Analysis and Impacts on 7Be Concentrations Wed, 22 Jun 2016 08:40:46 +0000 http://www.hindawi.com/journals/amete/2016/8026018/ The present paper describes and characterizes the air mass circulation during the heat-wave events registered during the period 2005–2014 over Spain, paying special attention to the role of the Saharan circulations. Backward trajectories at 500, 1500, and 3000 m in Seville (south), Madrid (centre), and Bilbao (north) during the thirteen heat-wave events identified are analysed. Finally, the impact of the heat-wave events and of each advection pattern on 7Be activity concentrations is also analysed. The heat-wave events are characterized roughly by western, southern, and nearby advections, with a higher frequency of the first two types. The analysis shows an increase of African air masses with height, presenting a different spatial impact over Spain, with a decreasing occurrence and a decrease in the simultaneous occurrence percentage from south to north. On average, the 7Be activity concentrations during these events show an increase of concentrations in central (21%) and southern (18%) areas and a decrease in northern (13%) Spain. This increase is not associated with Saharan air masses but instead with the arrival of distant westerly air masses. M. A. Hernández-Ceballos, E. Brattich, and G. Cinelli Copyright © 2016 M. A. Hernández-Ceballos et al. All rights reserved. Attenuation Correction Effects in Rainfall Estimation at X-Band Dual-Polarization Radar: Evaluation with a Dense Rain Gauge Network Mon, 20 Jun 2016 12:05:34 +0000 http://www.hindawi.com/journals/amete/2016/9716535/ The effects of attenuation correction in rainfall estimation with X-band dual-polarization radar were investigated with a dense rain gauge network. The calibration bias in reflectivity () was corrected using a self-consistency principle. The attenuation correction of and the differential reflectivity () were performed by a path integration method. After attenuation correction, and were significantly improved, and their scatter plots matched well with the theoretical relationship between and . The comparisons between the radar rainfall estimation and the rain gauge rainfall were investigated using the bulk statistics with different temporal accumulations and spatial averages. The bias significantly improves from 70% to 0% with . However, the improvement with was relatively small, from 3% to 1%. This indicated that rainfall estimation using a polarimetric variable was more robust at attenuation than was a single polarimetric variable method. The bias did not show improvement in comparisons between the temporal accumulations or the spatial averages in either rainfall estimation method. However, the random error improved from 68% to 25% with different temporal accumulations or spatial averages. This result indicates that temporal accumulation or spatial average (aggregation) is important to reduce random error. Young-A Oh, DaeHyung Lee, Sung-Hwa Jung, Kyung-Yeub Nam, and GyuWon Lee Copyright © 2016 Young-A Oh et al. All rights reserved. A Method to Assess Localized Impact of Better Floodplain Topography on Flood Risk Prediction Sun, 19 Jun 2016 06:58:25 +0000 http://www.hindawi.com/journals/amete/2016/6408319/ Many studies have highlighted the need for a higher accuracy global digital elevation model (DEM), mainly in river floodplains and deltas and along coastlines. In this paper, we present a method to infer the impact of a better DEM on applications and science using the Lower Zambezi basin as a use case. We propose an analysis based on a targeted observation algorithm to evaluate potential data acquisition subregions in terms of their impact on the prediction of flood risk over the entire study area. Consequently, it becomes trivial to rank these subregions in terms of their contribution to the overall accuracy of flood prediction. The improvement from better topography data may be expressed in terms of economic output and population affected, providing a multifaceted assessment of the value of acquiring better elevation data. Our results highlight the notion that having higher resolution measurements would improve our current large-scale flood inundation prediction capabilities in the Lower Zambezi by at least 30% and significantly reduce the number of people affected as well as the economic loss associated with high magnitude flooding. We believe this procedure to be simple enough to be applied to other regions where high quality topographic and hydrodynamic data are currently unavailable. Guy J.-P. Schumann and Konstantinos M. Andreadis Copyright © 2016 Guy J.-P. Schumann and Konstantinos M. Andreadis. All rights reserved. Hydrometeorology and Hydroclimate Sun, 19 Jun 2016 06:13:55 +0000 http://www.hindawi.com/journals/amete/2016/1487890/ Christophe Cudennec, Alexander Gelfan, Liliang Ren, and Mohamed Slimani Copyright © 2016 Christophe Cudennec et al. All rights reserved. A Multimethod Approach towards Assessing Urban Flood Patterns and Its Associated Vulnerabilities in Singapore Thu, 16 Jun 2016 12:29:48 +0000 http://www.hindawi.com/journals/amete/2016/7159132/ We investigated flooding patterns in the urbanised city-state of Singapore through a multimethod approach combining station precipitation data with archival newspaper and governmental records; changes in flash floods frequencies or reported impacts of floods towards Singapore society were documented. We subsequently discussed potential flooding impacts in the context of urban vulnerability, based on future urbanisation and forecasted precipitation projections for Singapore. We find that, despite effective flood management, (i) significant increases in reported flash flood frequency occurred in contemporary (post-2000) relative to preceding (1984–1999) periods, (ii) these flash floods coincide with more localised, “patchy” storm events, (iii) storms in recent years are also more intense and frequent, and (iv) floods result in low human casualties but have high economic costs via insurance damage claims. We assess that Singapore presently has low vulnerability to floods vis-à-vis other regional cities largely due to holistic flood management via consistent and successful infrastructural development, widespread flood monitoring, and effective advisory platforms. We conclude, however, that future vulnerabilities may increase from stresses arising from physical exposure to climate change and from demographic sensitivity via rapid population growth. Anticipating these changes is potentially useful in maintaining the high resilience of Singapore towards this hydrometeorological hazard. Winston T. L. Chow, Brendan D. Cheong, and Beatrice H. Ho Copyright © 2016 Winston T. L. Chow et al. All rights reserved. Improving the Distributed Hydrological Model Performance in Upper Huai River Basin: Using Streamflow Observations to Update the Basin States via the Ensemble Kalman Filter Thu, 16 Jun 2016 10:00:45 +0000 http://www.hindawi.com/journals/amete/2016/4921616/ This study investigates the capability of improving the distributed hydrological model performance by assimilating the streamflow observations. Incorrectly estimated model states will lead to discrepancies between the observed and estimated streamflow. Consequently, streamflow observations can be used to update the model states, and the improved model states will eventually benefit the streamflow predictions. This study tests this concept in upper Huai River basin. We assimilate the streamflow observations sequentially into the Soil and Water Assessment Tool (SWAT) using the ensemble Kalman filter (EnKF) to update the model states. Both synthetic experiments and real data application are used to demonstrate the benefit of this data assimilation scheme. The experiment shows that assimilating the streamflow observations at interior sites significantly improves the streamflow predictions for the whole basin. Assimilating the catchment outlet streamflow improves the streamflow predictions near the catchment outlet. In real data case, the estimated streamflow at the catchment outlet is significantly improved by assimilating the in situ streamflow measurements at interior gauges. Assimilating the in situ catchment outlet streamflow also improves the streamflow prediction of one interior location on the main reach. This may demonstrate that updating model states using streamflow observations can constrain the flux estimates in distributed hydrological modeling. Yongwei Liu, Wen Wang, Yiming Hu, and Wei Cui Copyright © 2016 Yongwei Liu et al. All rights reserved. Variability in Dust Observed over China Using A-Train CALIOP Instrument Thu, 16 Jun 2016 08:54:04 +0000 http://www.hindawi.com/journals/amete/2016/1246590/ Patterns of dust aerosol variation over China are analyzed using A-Train CALIOP and precipitation, soil moisture, and vegetation coverage datasets during the period of 2007 and 2014. Spatially, dust is mostly prominent over northwestern China, with the highest and most widespread dust activities being in Taklimakan Desert. Dust is generally distributed across the atmosphere up to 5 km altitude, with a peak of DAFOD around 3 km. The dust layer has a significant geographical and seasonal drifting, with higher altitude in spring and summer and dust source regions (between 3 km and 5 km). Additionally, single dust layer is more often observed in a vertical column. Temporally, high amounts of dust aerosol (C-DAFOD as high as 0.08) experienced in spring subsequently continuous decrease until the spring of next year. The correlation coefficients between the latitude averaged column integrated dust aerosol feature optical depth (C-DAFOD) and precipitation, soil moisture, and vegetation coverage are −0.65, −0.81, and −0.77, respectively. The correlation coefficients of seasonal mean C-DAFOD with the three factors are −0.15, −0.67, and −0.35, respectively. The analysis showed dust and the other three factors are negatively correlated. Overall, dust over China shows considerable spatial, temporal, and vertical variations. Hui Xu, Fengjie Zheng, and Wenhao Zhang Copyright © 2016 Hui Xu et al. All rights reserved. Spatial and Temporal Variability of Sea Surface Temperature in Eastern Marginal Seas of China Wed, 15 Jun 2016 12:37:29 +0000 http://www.hindawi.com/journals/amete/2016/3820720/ Spatial mean value evolution, long-term mean pattern, and seasonal as well as interannual variability of sea surface temperature (SST) in Eastern Marginal Seas of China (EMSC) are reanalyzed based on thirty years’ NOAA optimum interpolation (OI) 1/4 degrees’ daily SST data. Temporal evolution of the spatial mean value shows a very marked annual cycle and a weak warming tendency (0.03437°C/year). Spatial distribution of the long-term mean value shows some more fine spatial structure of SST compared to previous studies. Over 90% of the temporal variability can be explained by the annual harmonic whose amplitude is one order larger than that of the semiannual harmonic. In addition, the annual harmonic amplitude distribution is consistent with that of the value of standard deviation. In order to investigate the interannual variation of SST, the EMSC SST interannual index was constructed. Based on wavelet analysis, a significant peak around 3.3 years was found in the EMSC SST interannual index. Further analysis demonstrated that the interannual variability of SST is linked with El Niño-Southern Oscillation (ENSO) teleconnection, through which anomalous surface heat flux warms or cools the EMSC during El Niño or La Niña events. Renhao Wu, Jianmin Lin, and Bo Li Copyright © 2016 Renhao Wu et al. All rights reserved. The Impacts of Different PBL Schemes on the Simulation of PM2.5 during Severe Haze Episodes in the Jing-Jin-Ji Region and Its Surroundings in China Tue, 07 Jun 2016 10:57:32 +0000 http://www.hindawi.com/journals/amete/2016/6295878/ In this study, three schemes [Yonsei University (YSU), Mellor-Yamada-Janjic (MYJ), and Bougeault-Lacarrère (Boulac)] were employed in the Weather Research and Forecasting/Chemistry (WRF-Chem) model to simulate the severe haze that occurred in February 2014 in the Jing-Jin-Ji region and its surroundings. The PM2.5 concentration simulated using the three schemes, together with the meteorological factors closely related to PM2.5 (wind speed, local vertical diffusivity, and PBL height), was evaluated through comparison with observations. The results indicated that the eastern plain cities produced better simulation results than the western cities, and the cities under the eastern root of Taihang Mountain produced the worst results in simulating high PM2.5 concentration in haze. All three schemes simulated very similar variation trends of the surface PM2.5 concentration compared with observations. The diurnal variations of simulated surface PM2.5 were not as reasonable as their reflection of daily averaged variation. The simulated concentrations of surface PM2.5 using the YSU, MYJ, and Boulac schemes all showed large negative errors during daytime in polluted days due to their inefficient descriptions of local atmospheric stability or diffusion processes in haze. The lower ability of PBL schemes in distinguishing the diffusion between haze and clean days in the complex topography areas in China is an important problem for PM2.5 forecasting, which is worthy of being studied in detail. Tian Li, Hong Wang, Tianliang Zhao, Min Xue, Yaqiang Wang, Huizheng Che, and Chao Jiang Copyright © 2016 Tian Li et al. All rights reserved. Influence of Hydrological Model Selection on Simulation of Moderate and Extreme Flow Events: A Case Study of the Blue Nile Basin Tue, 31 May 2016 16:05:49 +0000 http://www.hindawi.com/journals/amete/2016/7148326/ Five hydrological models were applied based on data from the Blue Nile Basin. Optimal parameters of each model were obtained by automatic calibration. Model performance was tested under both moderate and extreme flow conditions. Extreme events for the model performance evaluation were extracted based on seven criteria. Apart from graphical techniques, there were nine statistical “goodness-of-fit” metrics used to judge the model performance. It was found that whereas the influence of model selection may be minimal in the simulation of normal flow events, it can lead to large under- and/or overestimations of extreme events. Besides, the selection of the best model for extreme events may be influenced by the choice of the statistical “goodness-of-fit” measures as well as the criteria for extraction of high and low flows. It was noted that the use of overall water-balance-based objective function not only is suitable for moderate flow conditions but also influences the models to perform better for high flows than low flows. Thus, the choice of a particular model is recommended to be made on a case by case basis with respect to the objectives of the modeling as well as the results from evaluation of the intermodel differences. Charles Onyutha Copyright © 2016 Charles Onyutha. All rights reserved. Mesoscale Spatial Variability of Linear Trend of Precipitation Statistics in Korean Peninsula Tue, 31 May 2016 09:09:19 +0000 http://www.hindawi.com/journals/amete/2016/3809719/ This study analyzed the spatial variability of the linear trend of the precipitation mean, variance, lag-1 autocorrelation coefficient, and probability of dryness (PD) based on the precipitation data between 1981 and 2015 observed at 65 rain gages located across Korean Peninsula. While the result of the Mann-Kendall test based on the yearly statistics showed no temporal trend at most of the gage locations, the same test based on the 20-yearly statistics showed that statistically significant temporal trend exists at 54% (mean), 60% (variance), 61% (autocorrelation), and 61% (PD) among the total 65 rain gages. In addition, this study produced the map of the linear trend of the precipitation statistics. The map showed a clear regional and seasonal tendency implying that the impact of the climate change varies significantly within Korea. The variogram analysis revealed that the approximate characteristic scale of linear trend of hourly and daily precipitation statistics ranges between 50 km and 200 km and between 100 km and 250 km, respectively. This characteristic scale is significantly smaller than the spatial scale of atmospheric circulation, which suggests that future water resources management plans of Korea should consider this mesoscale variability that otherwise can be missed if it is based only on the GCM simulation results. Jaehyeon Lee, Jaehyun Ahn, Eunsoo Choi, and Dongkyun Kim Copyright © 2016 Jaehyeon Lee et al. All rights reserved. Verification of Forecast Weather Surface Variables over Vietnam Using the National Numerical Weather Prediction System Tue, 31 May 2016 06:49:52 +0000 http://www.hindawi.com/journals/amete/2016/8152413/ The national numerical weather prediction system of Vietnam is presented and evaluated. The system is based on three main models, namely, the Japanese Global Spectral Model, the US Global Forecast System, and the US Weather Research and Forecasting (WRF) model. The global forecast products have been received at 0.25- and 0.5-degree horizontal resolution, respectively, and the WRF model has been run locally with 16 km horizontal resolution at the National Center for Hydro-Meteorological Forecasting using lateral conditions from GSM and GFS. The model performance is evaluated by comparing model output against observations of precipitation, wind speed, and temperature at 168 weather stations, with daily data from 2010 to 2014. In general, the global models provide more accurate forecasts than the regional models, probably due to the low horizontal resolution in the regional model. Also, the model performance is poorer for stations with altitudes greater than 500 meters above sea level (masl). For tropical cyclone performance validations, the maximum wind surface forecast from global and regional models is also verified against the best track of Joint Typhoon Warning Center. Finally, the model forecast skill during a recent extreme rain event in northeast Vietnam is evaluated. Tien Du Duc, Lars Robert Hole, Duc Tran Anh, Cuong Hoang Duc, and Thuy Nguyen Ba Copyright © 2016 Tien Du Duc et al. All rights reserved. Probabilistic Dressing of a Storm Surge Prediction in the Adriatic Sea Mon, 30 May 2016 09:42:18 +0000 http://www.hindawi.com/journals/amete/2016/3764519/ Providing a reliable, accurate, and fully informative storm surge forecast is of paramount importance for managing the hazards threatening coastal environments. Specifically, a reliable probabilistic forecast is crucial for the management of the movable barriers that are planned to become operational in 2018 for the protection of Venice and its lagoon. However, a probabilistic forecast requires multiple simulations and a considerable computational time, which makes it expensive in real-time applications. This paper describes the ensemble dressing method, a cheap operational flood prediction system that includes information about the uncertainty of the ensemble members by computing it directly from the meteorological input and the local spread distribution, without requiring multiple forecasts. Here, a sophisticated error distribution form is developed, which includes the superposition of the uncertainty caused by inaccuracies of the ensemble prediction system, which depends on surge level and lead time, and the uncertainty of the meteorological forcing, which is described using a combination of cross-basin pressure gradients. The ensemble dressing is validated over a 3-month-long period in the year 2010, during which an exceptional sequence of storm surges occurred. Results demonstrate that this computationally cheap method can provide an acceptably realistic estimate of the uncertainty. R. Mel and P. Lionello Copyright © 2016 R. Mel and P. Lionello. All rights reserved. Attribute Analysis of Aridity Variability in North Xinjiang, China Sun, 29 May 2016 12:58:39 +0000 http://www.hindawi.com/journals/amete/2016/9610960/ Identifying the dominant meteorological factors affecting aridity variability can improve our understanding of climate change and its future trend in arid and semiarid regions. This study investigated the spatiotemporal aridity variability in North Xinjiang, China, from 1961 to 2013, based on the UNESCO aridity index (precipitation/potential evapotranspiration), and analyzed its association with meteorological factors. The results suggest that North Xinjiang is becoming more humid with an increasing trend in aridity index. Precipitation, temperature, and relative humidity have positive correlation with aridity, and evapotranspiration, sunshine hours, and wind speed have negative correlation with aridity. Wind speed and sunshine hours have a higher sensitivity and more contribution to aridity. This study provides an understanding of the effect of recent climate change on drought in northwest China. Yanfeng Wu, Guangxin Zhang, Hong Shen, Y. Jun Xu, and Batur Bake Copyright © 2016 Yanfeng Wu et al. All rights reserved. Impact of Climate Change on Hydrologic Extremes in the Upper Basin of the Yellow River Basin of China Sun, 29 May 2016 07:37:01 +0000 http://www.hindawi.com/journals/amete/2016/1404290/ To reveal the revolution law of hydrologic extremes in the next 50 years and analyze the impact of climate change on hydrologic extremes, the following main works were carried on: firstly, the long duration (15 d, 30 d, and 60 d) rainfall extremes according to observed time-series and forecast time-series by dynamical climate model product (BCC-CSM-1.1) were deduced, respectively, on the basis that the quantitative estimation of the impact of climate change on rainfall extremes was conducted; secondly, the SWAT model was used to deduce design flood with the input of design rainfall for the next 50 years. On this basis, quantitative estimation of the impact of climate change on long duration flood volume extremes was conducted. It indicates that (1) the value of long duration rainfall extremes for given probabilities (1%, 2%, 5%, and 10%) of the Tangnaihai basin will rise with slight increasing rate from 1% to 6% in the next 50 years and (2) long duration flood volume extremes of given probabilities of the Tangnaihai basin will rise with slight increasing rate from 1% to 6% in the next 50 years. The conclusions may provide technical supports for basin level planning of flood control and hydropower production. Jun Wang, Zhongmin Liang, Dong Wang, Tian Liu, and Jing Yang Copyright © 2016 Jun Wang et al. All rights reserved. Statistical Analysis of Relationship between Daytime Lidar-Derived Planetary Boundary Layer Height and Relevant Atmospheric Variables in the Semiarid Region in Northwest China Thu, 19 May 2016 08:57:55 +0000 http://www.hindawi.com/journals/amete/2016/5375918/ Accurate identification of key parameters for data assimilation is important in simulating the planetary boundary layer height (PBLH) and structure evolution in numerical weather prediction models. In this study, surface observational data and lidar-derived PBLH on 42 cloudless days from June 2007 to May 2008 are used to quantify the statistical relationships between surface parameters and the PBLH at a semiarid climate observational site in Northwest China. The results indicate that surface upward long wave radiation, surface temperature, and surface sensible heat fluxes show strong correlations with the PBLH with correlation coefficients at a range of 0.63–0.72. But these parameters show varying correlation response time to the different stages of PBL development. Furthermore, the air temperature shows the highest correlation with the PBLH near the surface and the correlation decreases with increasing height. Ruijun Dang, Hong Li, Zhiguo Liu, and Yi Yang Copyright © 2016 Ruijun Dang et al. All rights reserved. A Simulation and Validation of CLM during Freeze-Thaw on the Tibetan Plateau Tue, 17 May 2016 07:24:44 +0000 http://www.hindawi.com/journals/amete/2016/9476098/ The applicability of a new soil hydraulic property of frozen soil scheme applied in Community Land Model 4.5 (CLM4.5), in conjunction with an impedance factor for the presence of soil ice, was validated through two offline numerical simulations conducted at Madoi (GS) and Zoige (ZS) on the Tibetan Plateau (TP). Sensitivity analysis was conducted via replacing the new soil hydraulic property scheme in CLM4.5 by the old one, using default CLM4.5 runs as reference. Results indicated that the new parameterization scheme ameliorated the surface dry biases at ZS but enlarged the wet biases which existed at GS site due to ignoring the gravel effect. The wetter surface condition in CLM4.5 also leads to a warmer surface soil temperature because of the greater heat capacity of liquid water. In addition, the combined impact of new soil hydraulic property schemes and the ice impedance function on the simulated soil moisture lead to the more reasonable simulation of the starting dates of freeze-thaw cycle, especially at the thawing stage. The improvements also lead to the more reasonable turbulent fluxes simulations. Meanwhile, the decreased snow cover fraction in CLM4.5 resulted in a lower albedo, which tended to increase net surface radiation compared to previous versions. Further optimizing is needed to take the gravel into account in the numerical description of thermal-hydrological interactions. Xuewei Fang, Siqiong Luo, Shihua Lyu, Boli Chen, Yu Zhang, Di Ma, and Yan Chang Copyright © 2016 Xuewei Fang et al. All rights reserved. Coupling WRF Double-Moment 6-Class Microphysics Schemes to RRTMG Radiation Scheme in Weather Research Forecasting Model Thu, 12 May 2016 12:27:53 +0000 http://www.hindawi.com/journals/amete/2016/5070154/ A method to explicitly calculate the effective radius of hydrometeors in the Weather Research Forecasting (WRF) double-moment 6-class (WDM6) microphysics scheme is designed to tackle the physical inconsistency in cloud properties between the microphysics and radiation processes. At each model time step, the calculated effective radii of hydrometeors from the WDM6 scheme are linked to the Rapid Radiative Transfer Model for GCMs (RRTMG) scheme to consider the cloud effects in radiative flux calculation. This coupling effect of cloud properties between the WDM6 and RRTMG algorithms is examined for a heavy rainfall event in Korea during 25–27 July 2011, and it is compared to the results from the control simulation in which the effective radius is prescribed as a constant value. It is found that the derived radii of hydrometeors in the WDM6 scheme are generally larger than the prescribed values in the RRTMG scheme. Consequently, shortwave fluxes reaching the ground (SWDOWN) are increased over less cloudy regions, showing a better agreement with a satellite image. The overall distribution of the 24-hour accumulated rainfall is not affected but its amount is changed. A spurious rainfall peak over the Yellow Sea is alleviated, whereas the local maximum in the central part of the peninsula is increased. Soo Ya Bae, Song-You Hong, and Kyo-Sun Sunny Lim Copyright © 2016 Soo Ya Bae et al. All rights reserved. Satellite Retrieval of Surface Evapotranspiration with Nonparametric Approach: Accuracy Assessment over a Semiarid Region Wed, 11 May 2016 11:49:52 +0000 http://www.hindawi.com/journals/amete/2016/1584316/ Surface evapotranspiration (ET) is one of the key surface processes. Reliable estimation of regional ET solely from satellite data remains a challenge. This study applies recently proposed nonparametric (NP) approach to retrieve surface ET, in terms of latent heat flux (LE), over a semiarid region. The involved input parameters are surface net radiation, land surface temperature, near-surface air temperature, and soil heat flux, all of which are retrievals or products of the Moderate-Resolution Imaging Spectroradiometer (MODIS). Field observations are used as ground references, which were obtained from six eddy covariance (EC) sites with different land covers including desert, Gobi, village, orchard, vegetable field, and wetland. Our results show that the accuracy of LE retrievals varies with EC sites with a determination of coefficient from 0.02 to 0.76, a bias from −221.56 W/m2 to 143.77 W/m2, a relative error from 8.82% to 48.35%, and a root mean square error from 67.97 W/m2 to 239.55 W/m2. The error mainly resulted from the uncertainties from MODIS products or the retrieval of net radiation and soil heat flux in nonvegetated region. It highlights the importance of accurate retrieval of the input parameters from satellite data, which are the ongoing tasks of remote sensing community. Xin Pan, Yuanbo Liu, and Xingwang Fan Copyright © 2016 Xin Pan et al. All rights reserved. Quantitative Estimation of the Impact of Precipitation and Land Surface Change on Hydrological Processes through Statistical Modeling Tue, 10 May 2016 09:37:35 +0000 http://www.hindawi.com/journals/amete/2016/6130179/ Precipitation variability and land surface changes are the two primary factors that affect basin hydrology, and thus estimation of their impact is of great importance for sustainable development at a catchment scale. In this study, we investigated the long-term changes in precipitation and runoff, from 1961 to 2011, in the Yihe River basin by Mann-Kendall test. A new method of trend pattern was put forward and used to identify the trends of precipitation and runoff, which indicated that the basin had a decreasing trend in annual runoff. The change point occurred in the year 1985 dividing the long-term series into two periods. Precipitation elasticity and linear regression methods were used to quantify the impact of precipitation and land surface change on runoff and provided consistent results of the percentage change in an annual runoff for the postchange period. Use of these methods reveals that the reduction in annual runoff is mainly due to precipitation variability of 56.38–67.68% and land surface change of 43.62–32.32%, as estimated by precipitation elasticity and linear regression methods, respectively. Due to the rapid growth of urbanization, the land surface change increased from 1990 to 2010. The result of this study can provide a reference for the management of regional water resources. Muhammad Saifullah, Zhijia Li, Qiaoling Li, Muhammad Zaman, and Sarfraz Hashim Copyright © 2016 Muhammad Saifullah et al. All rights reserved. A Study of the Circulation Patterns Affecting Drought and Wet Years in Central Iran Thu, 05 May 2016 08:02:53 +0000 http://www.hindawi.com/journals/amete/2016/1843659/ The main objective of this research is to identify atmospheric circulation patterns involved in the occurrence of wet and dry periods using the PCA method. To this end, drought and wet periods (1982–2011) were calculated in central Iran. The results of PCA indicated that 42% of variance in geopotential height data at 500 HPa level was associated with the extension of subpolar lows elevation towards lower latitudes, which transmitted high elevation areas like Siberian highs to the south and formed high atmospheric stability in the study area. Therefore, the dominance of high elevation cores on the area was characterized by cold air descent and cloudlessness, which led to low precipitation and drought events. Moreover, the eight components in wet periods could explain 94% of data variation in geopotential height data. The results of PCA in wet period suggested that the first component with the highest frequency played a key role among circulation patterns, determining the dominant pattern in cold period of the year. Further, its negative phase indicated polar and Siberian highs with the remaining components, given the negative and positive phases of the centers, revealing atmospheric instability that entered the region from Mediterranean, Black, and Red sea, thereby marking the transition of the area from drought to the wet period. Kamal Omidvar, Mehran Fatemi, Mahdi Narangifard, and Khodakaram Hatami Bahman Beiglou Copyright © 2016 Kamal Omidvar et al. All rights reserved. Markov Chain Decomposition of Monthly Rainfall into Daily Rainfall: Evaluation of Climate Change Impact Wed, 04 May 2016 13:41:39 +0000 http://www.hindawi.com/journals/amete/2016/7957490/ This study evaluates the effect of climate change on daily rainfall, especially on the mean number of wet days and the mean rainfall intensity. Assuming that the mechanism of daily rainfall occurrences follows the first-order Markov chain model, the possible changes in the transition probabilities are estimated by considering the climate change scenarios. Also, the change of the stationary probabilities of wet and dry day occurrences and finally the change in the number of wet days are derived for the comparison of current (1x CO2) and 2x CO2 conditions. As a result of this study, the increase or decrease in the mean number of wet days was found to be not enough to explain all of the change in monthly rainfall amounts, so rainfall intensity should also be modified. The application to the Seoul weather station in Korea shows that about 30% of the total change in monthly rainfall amount can be explained by the change in the number of wet days and the remaining 70% by the change in the rainfall intensity. That is, as an effect of climate change, the increase in the rainfall intensity could be more significant than the increase in the wet days and, thus, the risk of flood will be much highly increased. Chulsang Yoo, Jinwook Lee, and Yonghun Ro Copyright © 2016 Chulsang Yoo et al. All rights reserved. Statistics and Analysis of the Relations between Rainstorm Floods and Earthquakes Wed, 04 May 2016 12:27:17 +0000 http://www.hindawi.com/journals/amete/2016/4629235/ The frequent occurrence of geophysical disasters under climate change has drawn Chinese scholars to pay their attention to disaster relations. If the occurrence sequence of disasters could be identified, long-term disaster forecast could be realized. Based on the Earth Degassing Effect (EDE) which is valid, this paper took the magnitude, epicenter, and occurrence time of the earthquake, as well as the epicenter and occurrence time of the rainstorm floods as basic factors to establish an integrated model to study the correlation between rainstorm floods and earthquakes. 2461 severe earthquakes occurred in China or within 3000 km from China and the 169 heavy rainstorm floods occurred in China over the past 200+ years as the input data of the model. The computational results showed that although most of the rainstorm floods have nothing to do with the severe earthquakes from a statistical perspective, some floods might relate to earthquakes. This is especially true when the earthquakes happen in the vapor transmission zone where rainstorms lead to abundant water vapors. In this regard, earthquakes are more likely to cause big rainstorm floods. However, many cases of rainstorm floods could be found after severe earthquakes with a large extent of uncertainty. Baodeng Hou, Yongxiang Wu, Jianhua Wang, Kai Wu, and Weihua Xiao Copyright © 2016 Baodeng Hou et al. All rights reserved. Long-Term Precipitation Analysis and Estimation of Precipitation Concentration Index Using Three Support Vector Machine Methods Sat, 30 Apr 2016 11:30:47 +0000 http://www.hindawi.com/journals/amete/2016/7912357/ The monthly precipitation data from 29 stations in Serbia during the period of 1946–2012 were considered. Precipitation trends were calculated using linear regression method. Three CLINO periods (1961–1990, 1971–2000, and 1981–2010) in three subregions were analysed. The CLINO 1981–2010 period had a significant increasing trend. Spatial pattern of the precipitation concentration index (PCI) was presented. For the purpose of PCI prediction, three Support Vector Machine (SVM) models, namely, SVM coupled with the discrete wavelet transform (SVM-Wavelet), the firefly algorithm (SVM-FFA), and using the radial basis function (SVM-RBF), were developed and used. The estimation and prediction results of these models were compared with each other using three statistical indicators, that is, root mean square error, coefficient of determination, and coefficient of efficiency. The experimental results showed that an improvement in predictive accuracy and capability of generalization can be achieved by the SVM-Wavelet approach. Moreover, the results indicated the proposed SVM-Wavelet model can adequately predict the PCI. Milan Gocic, Shahaboddin Shamshirband, Zaidi Razak, Dalibor Petković, Sudheer Ch, and Slavisa Trajkovic Copyright © 2016 Milan Gocic et al. All rights reserved. Implementation of the WSM5 and WSM6 Single Moment Microphysics Scheme into the RAMS Model: Verification for the HyMeX-SOP1 Wed, 27 Apr 2016 12:34:47 +0000 http://www.hindawi.com/journals/amete/2016/5094126/ This paper shows the results of the implementation of two widely used bulk microphysics parameterizations (BMP) into the Regional Atmospheric Modeling System to improve the Quantitative Precipitation Forecast (QPF). The schemes are the WSM5 and WSM6 (WRF-single-moment-microphysics classes 5 and 6). The RAMS is run at high horizontal resolution (4 km) over the whole Italian territory and, to mimic the operational context, it is initialized by the analysis/forecast cycle issued at 12 UTC by the European Centre for Medium Weather Range Forecast (ECMWF). The performance of the BMP is analysed for the period of September 11 to October 31, 2012, which span most of the Special Observing Period 1 (SOP1) of the hydrological cycle in the Mediterranean experiment (HyMeX). For this period a database of daily precipitation of thousands of rain gauges over the Italian territory is available. In SOP1 few hazardous events occurred over Italy and, for one of them, the model performance is shown in detail. The potential improvement gained by combining the model outputs with different BMP in a single forecast is finally explored. Stefano Federico Copyright © 2016 Stefano Federico. All rights reserved. Evapotranspiration Partitioning and Response to Abnormally Low Water Levels in a Floodplain Wetland in China Tue, 19 Apr 2016 14:39:22 +0000 http://www.hindawi.com/journals/amete/2016/3695427/ Evapotranspiration (ET) is an important component of the wetland water budget. Water level declines in Poyang Lake, the largest freshwater lake in China, have caused concerns, especially during low water levels. However, how wetland ET and its partitioning respond to abnormally low water levels is unclear. In this study, wetland ET was estimated with MODIS data and meteorological data. The wetland ET partitioning and its relationship with abnormally low water levels were analyzed for 2000–2013. The results showed that the water evaporation rate () was larger than the land ET rate (); the / ranged from 0.77 to 0.99. When the water level was below 12.8 m, the ET partition ratio was larger than 1, which indicates that wetland ET comes from land surface ET more than water evaporation. The negative standardized water level index (SWI) was used to represent an abnormally low water level in the wetland. Although the monthly wetland ET decreased as the negative SWI decreased, was higher than the average under negative SWI conditions from September to December, when the water level decreased. The abnormally low water level induced more water loss from the land surface, especially when the water level decreased, which reduced the available water resources along the wetland shore. Xiaosong Zhao and Yuanbo Liu Copyright © 2016 Xiaosong Zhao and Yuanbo Liu. All rights reserved. The Relationship between the Heat Disorder Incidence Rate and Heat Stress Indices at Yamanashi Prefecture in Japan Mon, 18 Apr 2016 10:00:48 +0000 http://www.hindawi.com/journals/amete/2016/9492815/ In recent years, the risk of heat disorder in daily life has increased dramatically because the thermal environment has been deteriorating. The main objective of this study was to examine regional differences in the relationship between heat disorder incidence rate and heat stress indices at Yamanashi Prefecture, Japan. Daily maximum air temperature and daily maximum WBGT were used as heat stress indices in each region. Nonlinear regression analysis was used to examine the regional difference in the relationship between the heat disorder incidence rate and heat stress indices in each region. The heat disorder incidence rate was correlated with both indices of heat stress in all regions. However, the more appropriate heat stress index for heat disorder prevention differed among regions. The distributions of heat stress indices, such as the slope of regression curve and the temperature threshold, differed in each region, irrespective of the index used. Therefore, the criteria for thermal conditions for heat disorder prevention need to be determined for each region, considering the regional characteristics of the relationship between the heat disorder incidence rate and heat stress indices. Shin Akatsuka, Tadashi Uno, and Masahiro Horiuchi Copyright © 2016 Shin Akatsuka et al. All rights reserved.