Advances in Meteorology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Projecting Future Climate Change Scenarios Using Three Bias-Correction Methods Sun, 14 Dec 2014 11:02:18 +0000 We performed bias correction in future climate change scenarios to provide better accuracy of models through adaptation to future climate change. The proposed combination of the change factor (CF) and quantile mapping (QM) methods combines the individual advantages of both methods for adjusting the bias in global circulation models (GCMs) and regional circulation models (RCMs). We selected a study site in Songwol-dong, Seoul, Republic of Korea, to test and assess our proposed method. Our results show that the combined CF + QM method delivers better performance in terms of correcting the bias in GCMs/RCMs than when both methods are applied individually. In particular, our proposed method considerably improved the bias-corrected precipitation by capturing both the high peaks and amounts of precipitation as compared to that from the CF-only and QM-only methods. Thus, our proposed method can provide high-accuracy bias-corrected precipitation data, which could prove to be highly useful in interdisciplinary studies across the world. Donghyuk Kum, Kyoung Jae Lim, Chun Hwa Jang, Jichul Ryu, Jae E. Yang, Seong Joon Kim, Dong Soo Kong, and Younghun Jung Copyright © 2014 Donghyuk Kum et al. All rights reserved. Application of Short-Range LIDAR in Early Alerting for Low-Level Windshear and Turbulence at Hong Kong International Airport Mon, 01 Dec 2014 11:35:31 +0000 Hong Kong Observatory currently uses a series of meteorological instruments, including long-range LIDAR (light detection and ranging) systems, to provide alerting services of low-level windshear and turbulence for Hong Kong International Airport. For some events that are smaller in spatial dimensions and are rapidly changing, such as low altitude windshear and turbulence associated with buildings or man-made structures, it would be necessary to involve meteorological instruments that offer greater spatial resolution. Therefore, the Observatory has set up a short-range LIDAR on the roof of the AsiaWorld-Expo during the summers over the past several years, conducting field research on the feasibility of strengthening early alerting for windshear and turbulence over the north runway’s eastern arrival runway (Runway 25RA) and developing an automated early alerting algorithm. This paper takes the pilot reports for Runway 25RA during the 2013 field research as verification samples, using different thresholds for radial wind velocity spatial and temporal changes detected by the short-range LIDAR to calculate the relative operating characteristic (ROC) curve, and analyzes its early alerting performance. K. K. Hon, P. W. Chan, Y. Y. Chiu, and Wenbo Tang Copyright © 2014 K. K. Hon et al. All rights reserved. Analysis and Discussion of Atmospheric Precursor of European Heat Summers Mon, 24 Nov 2014 09:56:47 +0000 The prediction of summers with notable droughts and heatwaves on the seasonal scale is challenging, especially in extratropical regions, since their development is not yet fully understood. Thus, monitoring and analysis of such summers are important tasks to close this knowledge gap. In a previous paper, the authors presented hints that extreme summers are connected with specific conditions during the winter-spring transition season. Here, these findings are further discussed and analysed in the context of the Earth’s circulation systems. No evidence for a connection between the North Atlantic Oscillation or the Arctic Oscillation during the winter-spring transition and extremely hot and dry summers is found. However, inspection of the geopotential at 850 hPa shows that a Greenland-North Sea-Dipole is connected with extreme summers in Central Europe. This motivated the introduction of the novel Greenland-North Sea-Dipole-Index, GNDI. However, using this index as predictor would lead to one false alarm and one missed event in the time series analysed (1958–2011). Hints are found that the disturbance of the “dipole-summer” connection is due to El Niño/Southern Oscillation (ENSO). To consider the ENSO effect, the novel Central European Drought Index (CEDI) has been developed, which is composed of the GNDI and the Bivariate ENSO Time Series Index. The CEDI enables a correct indication of all extremely hot and dry summers between 1958 and 2011 without any false alarm. Christine Träger-Chatterjee, Richard W. Müller, and Jörg Bendix Copyright © 2014 Christine Träger-Chatterjee et al. All rights reserved. Prediction of Tropical Cyclones’ Characteristic Factors on Hainan Island Using Data Mining Technology Thu, 20 Nov 2014 12:55:20 +0000 A new methodology combining data mining technology with statistical methods is proposed for the prediction of tropical cyclones’ characteristic factors which contain latitude, longitude, the lowest center pressure, and wind speed. In the proposed method, the best track datasets in the years 1949~2012 are used for prediction. Using the method, effective criterions are formed to judge whether tropical cyclones land on Hainan Island or not. The highest probability of accurate judgment can reach above 79%. With regard to TCs which are judged to land on Hainan Island, related prediction equations are established to effectively predict their characteristic factors. Results show that the average distance error is improved compared with the National Meteorological Centre of China. Ruixu Zhou, Wensheng Gao, Bowen Zhang, Xianggan Fu, Qinzhu Chen, Song Huang, and Yafeng Liang Copyright © 2014 Ruixu Zhou et al. All rights reserved. The Influence of Climate Factors, Meteorological Conditions, and Boundary-Layer Structure on Severe Haze Pollution in the Beijing-Tianjin-Hebei Region during January 2013 Mon, 17 Nov 2014 14:32:25 +0000 The air-pollution episodes in China in January 2013 were the most hazardous in the Beijing-Tianjin-Hebei (BTH) region. PM2.5, AOD, and long-term visibility data, along with various climate and meteorological factors and the boundary-layer structure, were used to investigate the cause of the heavy-haze pollution events in January 2013. The result suggests that unfavorable diffusion conditions (weak surface winds and high humidity) and high primary-pollutant emissions have induced heavy-haze pollution in the BTH region over the past two decades. A sudden stratospheric warming (SSW), weak East Asian winter monsoon, a weak Siberian High, weak meridional circulation, southerly wind anomalies in the lower troposphere, and abnormally weak surface winds and high humidity were responsible for the severe haze pollution events, rather than an abrupt increase in emissions. Heavy/severe haze pollution is associated with orographic wind convergence zones along the Taihang and Yanshan Mountains, slight winds (1.7∼2.1 m/s), and high humidity (70%∼90%), which limits the diffusion of pollutants and facilitates the hygroscopic growth of aerosols. Recirculation and regional transport, along with the poorest diffusion conditions and favorable conditions for hygroscopic growth of aerosols and secondary transformation under the high emission, led to explosive growth and the record high hourly average concentration of PM2.5 in Beijing. Lili Wang, Nan Zhang, Zirui Liu, Yang Sun, Dongsheng Ji, and Yuesi Wang Copyright © 2014 Lili Wang et al. All rights reserved. Relative Contribution of the Topographic Influence on the Triangle Approach for Evapotranspiration Estimation over Mountainous Areas Wed, 05 Nov 2014 08:01:27 +0000 Evapotranspiration (ET) is an important component of the water budget. Estimation ET through remote sensing over a mountainous terrain is typically obstructed by topographic effects. In this paper, topographic corrections were applied to ET estimates using the surface-air temperature difference-Normalized Difference Vegetation Index (()-NDVI) triangle method with MODIS data for the Taihu Basin in China. The effect of topography on ET was evaluated over an area with a complex terrain. After applying the topographic correction, the results indicate that the ET decreased with elevation and slope. The slope had a stronger impact on ET than the elevation, which caused the corrected ET to decrease by 90% from 6.8 mm day−1 to 0.6 mm day−1 for slopes over 50°. On average, the corrected ET decreased by 10.4% and 32.1% for north- and south-facing slopes, respectively. The ET corrected using the triangle method strongly depended on the evaporative fraction correction, which can mainly be attributed to the surface temperature correction. We conclude that a topographic correction is necessary when the triangle method is applied to areas with a complex terrain. Xiaosong Zhao and Yuanbo Liu Copyright © 2014 Xiaosong Zhao and Yuanbo Liu. All rights reserved. Trends in Dryness Index Based on Potential Evapotranspiration and Precipitation over 1961–2099 in Xinjiang, China Tue, 04 Nov 2014 13:21:12 +0000 Under the background of global warming, deep understanding for drought-related index is important. The spatial distributions and trends in annual mean (AM) climatic data, including , , and in Xinjiang, China, were analyzed. Statistical downscaling model (SDSM) was applied. Future , , and series were generated and used to analyze their temporal trends, along with the historical climatic data. The results showed that (1) over 1960–2010, varied greatly and ranged from 1.5 to 479.6. Trends in decreased significantly. The regional climate turned to be from arid to humid in the past; (2) over 2015–2099, ranged between 1.9 and 198.5 under A2 scenario and 1.6 and 130.4 under B2 scenario. Trends in decreased insignificantly under A2 scenario and significantly under B2 scenario, indicating a weak drought stress from the future climate; (3) the modified Mann-Kendal (MKK) test generally decreased the significance of the trends because it considered the limitation of serial autocorrelation. Robust trend test of MMK method was recommended considering its rigor property. In conclusion, the drought in Xinjiang tends to be relieved over 2015–2099 compared to 1960–2010. Yi Li and Mudan Zhou Copyright © 2014 Yi Li and Mudan Zhou. All rights reserved. The Influence of Topography on East African October to December Climate: Sensitivity Experiments with RegCM4 Tue, 21 Oct 2014 00:00:00 +0000 The influence of topography on east African climate is investigated using the International Centre for Theoretical Physics Regional Climate Model, with focus on October to December season. Results show that the mean rainfall (temperature) significantly reduces (increases) over the region when topography elevation is reduced. Based on the model, when topography over the selected region (KTU) is reduced to 25%, the mean rainfall (temperature) over east Africa is reduced (increased) by about 19% (1.4°C). The maximum rainfall (temperature) reduction (increase) is however observed around the region over which topography is reduced. The reduction in topography elevation resulted in an anomalous moisture divergence at low level and descending motion over the region. KTU topography enhances the surface heat flux over KTU region and tends to enhance convection over both KTU and the east African region. The topography also helps in the generation of the high frequency mesoscale and subsynoptic disturbances over the region. These disturbances produce precipitation over the region and may also enhance precipitation systems over remote areas due to propagation of the disturbances. The magnitude of the zonal wind speed at 850 hpa increases with the decrease in topography elevation. Bob Alex Ogwang, Haishan Chen, Xing Li, and Chujie Gao Copyright © 2014 Bob Alex Ogwang et al. All rights reserved. Impact of Direct Soil Moisture and Revised Soil Moisture Index Methods on Hydrologic Predictions in an Arid Climate Wed, 15 Oct 2014 08:57:54 +0000 The soil and water assessment tool (SWAT) is a physically based model that is used extensively to simulate hydrologic processes in a wide range of climates around the world. SWAT uses spatial hydrometeorological data to simulate runoff through the computation of a retention curve number. The objective of the present study was to compare the performance of two approaches used for the calculation of curve numbers in SWAT, that is, the Revised Soil Moisture Index (SMI), which is based on previous meteorological conditions, and the Soil Moisture Condition II (SMCII), which is based on soil features for the prediction of flow. The results showed that the sensitive parameters for the SMI method are land-use and land-cover features. However, for the SMCII method, the soil and the channel are the sensitive parameters. The performances of the SMI and SMCII methods were analyzed using various indices. We concluded that the fair performance of the SMI method in an arid region may be due to the inherent characteristics of the method since it relies mostly on previous meteorological conditions and does not account for the soil features of the catchment. Milad Jajarmizadeh, Sobri bin Harun, Shamsuddin Shahid, Shatirah Akib, and Mohsen Salarpour Copyright © 2014 Milad Jajarmizadeh et al. All rights reserved. Evaluation of Coupled Model Forecasts of Ethiopian Highlands Summer Climate Tue, 14 Oct 2014 11:51:43 +0000 This study evaluates seasonal forecasts of rainfall and maximum temperature across the Ethiopian highlands from coupled ensemble models in the period 1981–2006, by comparison with gridded observational products (NMA + GPCC/CRU3). Early season forecasts from the coupled forecast system (CFS) are steadier than European community medium range forecast (ECMWF). CFS and ECMWF April forecasts of June–August (JJA) rainfall achieve significant fit (, 0.25, resp.), but ECMWF forecasts tend to have a narrow range with drought underpredicted. Early season forecasts of JJA maximum temperature are weak in both models; hence ability to predict water resource gains may be better than losses. One aim of seasonal climate forecasting is to ensure that crop yields keep pace with Ethiopia’s growing population. Farmers using prediction technology are better informed to avoid risk in dry years and generate surplus in wet years. Mark R. Jury Copyright © 2014 Mark R. Jury. All rights reserved. Dynamical Downscaling of Climate Change Impacts on Wind Energy Resources in the Contiguous United States by Using a Limited-Area Model with Scale-Selective Data Assimilation Mon, 22 Sep 2014 07:39:10 +0000 By using a limited-area model (LAM) in combination with the scale-selective data assimilation (SSDA) approach, wind energy resources in the contiguous United States (CONUS) were downscaled from IPCC CCSM3 global model projections for both current and future climate conditions. An assessment of climate change impacts on wind energy resources in the CONUS region was then conducted. Based on the downscaling results, when projecting into future climate under IPCC’s A1B scenario, the average annual wind speed experiences an overall shift across the CONUS region. From the current climate to the 2040s, the average annual wind speed is expected to increase from 0.1 to 0.2 m s−1 over the Great Plains, Northern Great Lakes Region, and Southwestern United States located southwest of the Rocky Mountains. When projecting into the 2090s from current climate, there is an overall increase in the Great Plains Region and Southwestern United States located southwest of the Rockies with a mean wind speed increase between 0 and 0.1 m s−1, while, the Northern Great Lakes Region experiences an even greater increase from current climate to 2090s than over the first few decades with an increase of mean wind speed from 0.1 to 0.4 m s−1. Bin Liu, Katelyn B. Costa, Lian Xie, and Fredrick H. M. Semazzi Copyright © 2014 Bin Liu et al. All rights reserved. Future Changes in Surface Runoff over Korea Projected by a Regional Climate Model under A1B Scenario Sun, 21 Sep 2014 09:29:25 +0000 This study assesses future change of surface runoff due to climate change over Korea using a regional climate model (RCM), namely, the Global/Regional Integrated Model System (GRIMs), Regional Model Program (RMP). The RMP is forced by future climate scenario, namely, A1B of Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The RMP satisfactorily reproduces the observed seasonal mean and variation of surface runoff for the current climate simulation. The distribution of monsoonal precipitation-related runoff is adequately captured by the RMP. In the future (2040–2070) simulation, it is shown that the increasing trend of temperature has significant impacts on the intra-annual runoff variation. The variability of runoff is increased in summer; moreover, the strengthened possibility of extreme occurrence is detected in the future climate. This study indicates that future climate projection, including surface runoff and its variability over Korea, can be adequately addressed on the RMP testbed. Furthermore, this study reflects that global warming affects local hydrological cycle by changing major water budget components. This study adduces that the importance of runoff should not be overlooked in regional climate studies, and more elaborate presentation of fresh-water cycle is needed to close hydrological circulation in RCMs. Ji-Woo Lee, Suryun Ham, Song-You Hong, Kei Yoshimura, and Minsu Joh Copyright © 2014 Ji-Woo Lee et al. All rights reserved. Multirule Based Diagnostic Approach for the Fog Predictions Using WRF Modelling Tool Sun, 21 Sep 2014 09:25:19 +0000 The prediction of fog onset remains difficult despite the progress in numerical weather prediction. It is a complex process and requires adequate representation of the local perturbations in weather prediction models. It mainly depends upon microphysical and mesoscale processes that act within the boundary layer. This study utilizes a multirule based diagnostic (MRD) approach using postprocessing of the model simulations for fog predictions. The empiricism involved in this approach is mainly to bridge the gap between mesoscale and microscale variables, which are related to mechanism of the fog formation. Fog occurrence is a common phenomenon during winter season over Delhi, India, with the passage of the western disturbances across northwestern part of the country accompanied with significant amount of moisture. This study implements the above cited approach for the prediction of occurrences of fog and its onset time over Delhi. For this purpose, a high resolution weather research and forecasting (WRF) model is used for fog simulations. The study involves depiction of model validation and postprocessing of the model simulations for MRD approach and its subsequent application to fog predictions. Through this approach model identified foggy and nonfoggy days successfully 94% of the time. Further, the onset of fog events is well captured within an accuracy of 30–90 minutes. This study demonstrates that the multirule based postprocessing approach is a useful and highly promising tool in improving the fog predictions. Swagata Payra and Manju Mohan Copyright © 2014 Swagata Payra and Manju Mohan. All rights reserved. Evaluation of Arctic Land Snow Cover Characteristics, Surface Albedo, and Temperature during the Transition Seasons from Regional Climate Model Simulations and Satellite Data Thu, 18 Sep 2014 08:03:54 +0000 This paper evaluates the simulated Arctic land snow cover duration, snow water equivalent, snow cover fraction, surface albedo, and land surface temperature in the regional climate model HIRHAM5 during 2008–2010, compared with various satellite and reanalysis data and one further regional climate model (COSMO-CLM). HIRHAM5 shows a general agreement in the spatial patterns and annual course of these variables, although distinct biases for specific regions and months are obvious. The most prominent biases occur for east Siberian deciduous forest albedo, which is overestimated in the simulation for snow covered conditions in spring. This may be caused by the simplified albedo parameterization (e.g., nonconsideration of different forest types and neglecting the effect of fallen leaves and branches on snow for deciduous tree forest). The land surface temperature biases mirror the albedo biases in their spatial and temporal structures. The snow cover fraction and albedo biases can explain the simulated land surface temperature bias of ca. −3°C over the Siberian forest area in spring. X. Zhou, H. Matthes, A. Rinke, K. Klehmet, B. Heim, W. Dorn, D. Klaus, K. Dethloff, and B. Rockel Copyright © 2014 X. Zhou et al. All rights reserved. Accumulation Studies at a High Elevation Glacier Site in Central Karakoram Wed, 17 Sep 2014 07:24:42 +0000 The precipitation conditions in central Karakoram are investigated on the basis of snow samples from high elevated snow pits at Urdok glacier from 2006 and the analysis of atmospheric transport trajectories in combination with the general, large scale pressure distribution. Our analysis shows that accumulation at the high elevated regions of the central Karakoram is dominated by the west wind circulation (WWC). Incursions of the South Asian monsoon (SAM) occur sometimes during the summer months accompanied by strong precipitation but play a minor role for the total accumulation amount. Dust layers found in the snow pits show a rare earth elements signature which indicates that the dust very likely originates from the arid regions of western China and Central Asia. Our trajectory calculations based on NCEP/NCAR reanalysis data confirm that especially during late spring and early summer the westerly flow is redirected over the Tarim basin to reach central Karakoram from an East/Southeast direction. The preservation of the layer structure and the clear seasonal signals in the snow pits indicate that locations above 5200 m in central Karakoram will be suitable places for retrieving longer climate records from ice cores. Christoph Mayer, Astrid Lambrecht, Hans Oerter, Margit Schwikowski, Elisa Vuillermoz, Nicola Frank, and Guglielmina Diolaiuti Copyright © 2014 Christoph Mayer et al. All rights reserved. The Role of the Dominant Modes of Precipitation Variability over Eastern Africa in Modulating the Hydrology of Lake Victoria Tue, 16 Sep 2014 11:44:58 +0000 Previous water budget studies over Lake Victoria basin have shown that there is near balance between rainfall and evaporation and that the variability of Lake Victoria levels is determined virtually entirely by changes in rainfall since evaporation is nearly constant. The variability of rainfall over East Africa is dominated by El Niño-Southern Oscillation (ENSO); however, the second and third most dominant rainfall climate modes also account for significant variability across the region. The relationship between ENSO and other significant modes of precipitation variability with Lake Victoria levels is nonlinear. This relationship should be studied to determine which modes need to be accurately modeled in order to accurately model Lake Victoria levels, which are important to the hydroelectric industry in East Africa. The objective of this analysis is to estimate the relative contributions of the dominant modes of annual precipitation variability to the modulation of Lake Victoria levels for the present day (1950–2012). The first mode of annual rainfall variability accounts for most of the variability in Lake Victoria levels, while the effects of the second and third modes are negligible even though these modes are also significant over the region. Kara A. Smith and Fredrick H. M. Semazzi Copyright © 2014 Kara A. Smith and Fredrick H. M. Semazzi. All rights reserved. Climate Change Scenarios of Precipitation Extremes in the Carpathian Region Based on an Ensemble of Regional Climate Models Tue, 16 Sep 2014 11:04:51 +0000 The study examines projected changes in precipitation extremes, aggregated on several time scales (1 hour, 1 day, and 5 days), in simulations of 12 regional climate models (RCMs) with high spatial resolution (~25 km). The study area is the Carpathian Basin (Central and Southeastern Europe) which has a complex topography and encompasses the whole territory of Slovakia and Hungary as well as major parts of Romania and western Ukraine. We focus on changes in mean seasonal maxima and high quantiles (50-year return values) projected for the late 21st century (time slice 2070–2099) in comparison to the control period (time slice 1961–1990), for summer and winter. The 50-year return values are estimated by means of a regional frequency analysis based on the region-of-influence method, which reduces random variability and leads to more reliable estimates of high quantiles. In winter, all examined characteristics of precipitation (seasonal totals, mean seasonal maxima, and 50-year return values for both short-term and multi-day aggregations) show similar patterns of projected increases for the late 21st century. In summer, by contrast, drying is projected for seasonal totals in all RCMs while increases clearly prevail for the 50-year return values. The projected increases are larger for short-term (hourly) extremes that are more directly related to convective activity than multiday extremes. This suggests that the probability of occurrence of flash floods may increase more than that of large-scale floods in a warmer climate. The within-ensemble variability (and associated uncertainty) is, nevertheless, much larger in summer than in winter. Ladislav Gaál, Romana Beranová, Kamila Hlavčová, and Jan Kyselý Copyright © 2014 Ladislav Gaál et al. All rights reserved. A Numerical Investigation of the Precipitation over Lake Victoria Basin Using a Coupled Atmosphere-Lake Limited-Area Model Mon, 15 Sep 2014 07:52:44 +0000 By using a coupled atmosphere-lake model, which consists of the Weather Research and Forecasting (WRF) model and the Princeton Ocean Model (POM), the present study generated realistic lake surface temperature (LST) over Lake Victoria and revealed the prime importance of LST on the precipitation pattern over the Lake Victoria Basin (LVB). A suite of sensitivity experiments was conducted for the selection of an optimal combination of physics options including cumulus, microphysics, and planetary boundary layer schemes for simulating precipitation over the LVB. The WRF-POM coupled system made a great performance on simulating the expected LST, which is featured with eastward temperature gradient as in the real bathymetry of the lake. Under thorough examination of diagnostic analysis, a distinguished diurnal phenomenon has been unveiled. The precipitation mainly occurs during the nocturnal peak between midnight and early in the morning, which is associated with the strong land breeze circulation, when the lake temperature is warmer than the adjacent land. Further exploration of vertical velocity, surface divergence pattern, and maximum radar reflectivity confirms such conjecture. The time-longitude analysis of maximum radar reflectivity over the entire lake also shows a noticeable pattern of dominating westward propagation. Xia Sun, Lian Xie, Fredrick H. M. Semazzi, and Bin Liu Copyright © 2014 Xia Sun et al. All rights reserved. New Role of Thermal Mapping in Winter Maintenance with Principal Components Analysis Tue, 09 Sep 2014 08:11:13 +0000 Thermal mapping uses IR thermometry to measure road pavement temperature at a high resolution to identify and to map sections of the road network prone to ice occurrence. However, measurements are time-consuming and ultimately only provide a snapshot of road conditions at the time of the survey. As such, there is a need for surveys to be restricted to a series of specific climatic conditions during winter. Typically, five to six surveys are used, but it is questionable whether the full range of atmospheric conditions is adequately covered. This work investigates the role of statistics in adding value to thermal mapping data. Principal components analysis is used to interpolate between individual thermal mapping surveys to build a thermal map (or even a road surface temperature forecast), for a wider range of climatic conditions than that permitted by traditional surveys. The results indicate that when this approach is used, fewer thermal mapping surveys are actually required. Furthermore, comparisons with numerical models indicate that this approach could yield a suitable verification method for the spatial component of road weather forecasts—a key issue currently in winter road maintenance. Mario Marchetti, Lee Chapman, Abderrahmen Khalifa, and Michel Buès Copyright © 2014 Mario Marchetti et al. All rights reserved. A Regionalization of Downscaled GCM Data Considering Geographical Features in a Mountainous Area Mon, 08 Sep 2014 08:23:04 +0000 This study establishes a methodology for the application of downscaled GCM data in a mountainous area having large spatial variations of rainfall and attempts to estimate the change of rainfall characteristics in the future under climate change. The Namhan river basin, which is in the mountainous area of the Korean peninsula, has been chosen as the study area. neural network-simple kriging with varying local means (ANN-SKlm) has been built by combining the artificial neural network, which is one of the general downscaling techniques, with the SKlm regionalization technique, which can reflect the geomorphologic characteristics. The ANN-SKlm technique was compared with the Thiessen technique and the ordinary kriging (OK) technique in the study area and the SKlm technique showed the best results. Future rainfall levels have been predicted by downscaling the data from CNRM-CM3 climate model, which was simulated under the A1B scenario. According to the results of future annual average rainfall by each regionalization technique, the Thiessen and OK techniques underestimated the future rainfall when compared to the ANN-SKlm technique. Therefore this methodology will be very useful for the prediction of future rainfall levels under climate change, most notably in a mountainous area. Soojun Kim, Jaewon Kwak, Hung Soo Kim, Yonsoo Kim, Narae Kang, Seung Jin Hong, and Jongso Lee Copyright © 2014 Soojun Kim et al. All rights reserved. Mitigating the Urban Heat Island Effect in Megacity Tehran Sun, 07 Sep 2014 09:44:16 +0000 Cities demonstrate higher nocturnal temperatures than surrounding rural areas, which is called “urban heat island” (UHI) effect. Climate change projections also indicate increase in the frequency and intensity of heat waves, which will intensify the UHI effect. As megacity Tehran is affected by severe heatwaves in summer, this study investigates its UHI characteristics and suggests some feasible mitigation strategies in order to reduce the air temperature and save energy. Temperature monitoring in Tehran shows clear evidence of the occurrence of the UHI effect, with a peak in July, where the urban area is circa 6 K warmer than the surrounding areas. The mobile measurements show a park cool island of 6-7 K in 2 central parks, which is also confirmed by satellite images. The effectiveness of three UHI mitigation strategies high albedo material (HAM), greenery on the surface and on the roofs (VEG), and a combination of them (HYBRID) has been studied using simulation with the microscale model ENVI-met. All three strategies show higher cooling effect in the daytime. The average nocturnal cooling effect of VEG and HYBRID (0.92, 1.10 K) is much higher than HAM (0.16 K), although high-density trees show a negative effect on nocturnal cooling. Sahar Sodoudi, Parisa Shahmohamadi, Ken Vollack, Ulrich Cubasch, and A. I. Che-Ani Copyright © 2014 Sahar Sodoudi et al. All rights reserved. Atmospheric Error Correction of the Laser Beam Ranging Sun, 07 Sep 2014 06:13:03 +0000 Atmospheric models based on surface measurements of pressure, temperature, and relative humidity have been used to increase the laser ranging accuracy by ray tracing. Atmospheric refraction can cause significant errors in laser ranging systems. Through the present research, the atmospheric effects on the laser beam were investigated by using the principles of laser ranging. Atmospheric correction was calculated for 0.532, 1.3, and 10.6 micron wavelengths through the weather conditions of Tehran, Isfahan, and Bushehr in Iran since March 2012 to March 2013. Through the present research the atmospheric correction was computed for meteorological data in base of monthly mean. Of course, the meteorological data were received from meteorological stations in Tehran, Isfahan, and Bushehr. Atmospheric correction was calculated for 11, 100, and 200 kilometers laser beam propagations under 30°, 60°, and 90° rising angles for each propagation. The results of the study showed that in the same months and beam emission angles, the atmospheric correction was most accurate for 10.6 micron wavelength. The laser ranging error was decreased by increasing the laser emission angle. The atmospheric correction with two Marini-Murray and Mendes-Pavlis models for 0.532 nm was compared. J. Saydi, A. Lotfalian, M. Abedi, J. Khalilzadeh, and H. Saghafifar Copyright © 2014 J. Saydi et al. All rights reserved. Changes in Surface Wind Speed over North America from CMIP5 Model Projections and Implications for Wind Energy Mon, 01 Sep 2014 00:00:00 +0000 The centennial trends in the surface wind speed over North America are deduced from global climate model simulations in the Climate Model Intercomparison Project—Phase 5 (CMIP5) archive. Using the 21st century simulations under the RCP 8.5 scenario of greenhouse gas emissions, 5–10 percent increases per century in the 10 m wind speed are found over Central and East-Central United States, the Californian Coast, and the South and East Coasts of the USA in winter. In summer, climate models projected decreases in the wind speed ranging from 5 to 10 percent per century over the same coastal regions. These projected changes in the surface wind speed are moderate and imply that the current estimate of wind power potential for North America based on present-day climatology will not be significantly changed by the greenhouse gas forcing in the coming decades. Sujay Kulkarni and Huei-Ping Huang Copyright © 2014 Sujay Kulkarni and Huei-Ping Huang. All rights reserved. Dust Identification over Arid and Semiarid Regions of Asia Using AIRS Thermal Infrared Channels Sun, 31 Aug 2014 14:37:07 +0000 Asia dust generated in northern China exerts significant influences on regional air quality, weather, and climate. In this study, a dust identification algorithm over arid and semiarid regions of Asia was proposed based on the thermal observations of atmospheric infrared sounder (AIRS). Firstly, a combination of the line-by-line (LBL) and discrete ordinates radiative transfer (DISORT) model was utilized to investigate the thermal infrared signatures of dust and cloud in 800–1250 cm−1 region. Secondly, six channels in the thermal infrared region were selected from AIRS to monitor dust from space, and a further sensitivity analysis for dust and cloud under different conditions was also performed. Then, the description of the detailed identification method was provided based on distinct thermal infrared signature of dust. At last, several dust events that observed in northern China between the period of 2008 and 2012 were analyzed, and the usefulness of monitoring the outbreaks of Asian dust was emphasized through the comparison with moderate resolution imaging spectroradiometer (MODIS) visible observations and cloud aerosol lidar with orthogonal polarization (CALIOP) data in this study. Hui Xu, Tianhai Cheng, Donghai Xie, Jiaguo Li, Yu Wu, and Hao Chen Copyright © 2014 Hui Xu et al. All rights reserved. Downscaling Maximum Temperatures to Subkilometer Resolutions in the Shenandoah National Park of Virginia, USA Sun, 31 Aug 2014 12:04:55 +0000 Downscaling future temperature projections to mountainous regions is vital for many applications, including ecological and water resource management. In this study, we demonstrate a method to downscale maximum temperatures to subkilometer resolutions using the Parameter-elevation Regression on Independent Slopes Model (PRISM). We evaluate the downscaling method with observations from a network of temperature sensors deployed along western and eastern slopes of Virginia’s Shenandoah National Park in the southern Appalachian Mountains. We find that the method overestimates mean July maximum temperatures by about 2°C (4°C) along the western (eastern) slopes. Based on this knowledge, we introduce corrections to generate maps of current and future maximum temperatures in the Shenandoah National Park. Temple R. Lee, Stephan F. J. De Wekker, and John E. B. Wofford Copyright © 2014 Temple R. Lee et al. All rights reserved. Automatic Tracking and Characterization of Cumulonimbus Clouds from FY-2C Geostationary Meteorological Satellite Images Sun, 31 Aug 2014 09:35:24 +0000 This paper presents an automated method to track cumulonimbus (Cb) clouds based on cloud classification and characterizes Cb behavior from FengYun-2C (FY-2C). First, a seeded region growing (SRG) algorithm is used with artificial neural network (ANN) cloud classification as preprocessing to identify consistent homogeneous Cb patches from infrared images. Second, a cross-correlation-based approach is used to track Cb patches within an image sequence. Third, 7 pixel parameters and 19 cloud patch parameters of Cb are derived. To assess the performance of the proposed method, 8 cases exhibiting different life stages and the temporal evolution of a single case are analyzed. The results show that (1) the proposed method is capable of locating and tracking Cb until dissipation and can account for the eventual splitting or merging of clouds; (2) compared to traditional brightness temperature (TB) thresholds-based cloud tracking methods, the proposed method reduces the uncertainty stemming from TB thresholds by classifying clouds with multichannel data in an advanced manner; and (3) the configuration and developmental stages of Cb that the method identifies are close to reality, suggesting that the characterization of Cb can provide detailed insight into the study of the motion and development of thunderstorms. Yu Liu, Du-Gang Xi, Zhao-Liang Li, and Chun-Xiang Shi Copyright © 2014 Yu Liu et al. All rights reserved. Monitoring of the Deposition of PAHs and Metals Produced by a Steel Plant in Taranto (Italy) Thu, 28 Aug 2014 00:00:00 +0000 A high time-resolved monitoring campaign of bulk deposition of PAHs and metals was conducted near the industrial area and at an urban background site in province of Taranto (Italy) in order to evaluate the impact of the biggest European steel plant. The deposition fluxes of the sum of detected PAHs at the industrial area ranged from 92 to 2432 ng m−2d−1. In particular the deposition fluxes of BaP, BaA, and BkF were, on average, 10, 14, and 8 times higher than those detected at the urban background site, respectively. The same finding was for metals. The deposition fluxes of Ni (19.8 µg m−2 d−1) and As (2.2 µg m−2 d−1) at the industrial site were about 5 times higher than those at the urban background site, while the deposition fluxes of Fe (57 mg m−2d−1) and Mn (1.02 mg m−2d−1) about 31 times higher. Precipitation and wind speed played an important role in PAH deposition fluxes. Fe and Mn fluxes at the industrial site resulted high when wind direction favored the transport of air masses from the steel plant to the receptor site. The impact of the industrial area was also confirmed by IP/(IP + BgP), IP/BgP, and BaP/BgP diagnostic ratios. M. Amodio, G. de Gennaro, A. Di Gilio, and M. Tutino Copyright © 2014 M. Amodio et al. All rights reserved. Litter Production and Nutrient Dynamic on a Moso Bamboo Plantation following an Extreme Disturbance of 2008 Ice Storm Thu, 28 Aug 2014 00:00:00 +0000 Ice storm is known to play a role in determining forest succession and litter dynamics constitute an important aspect of nutrient cycling in forest ecosystems. However, ice storm effects on amount and pattern of litterfall are not clearly understood. We investigated litter production and litter leaf nutrient dynamic in a moso bamboo plantation in China following an extreme disturbance of ice storm in 2008. The litterfall in on-years was significantly lower than in off-years. Ice storm caused total litterfall increasing from 16.68% to 35.60% and greatly disturbed the litterfall peak rhythm especially in the on-year. The litter leaf nutrient concentrations at two latitudes significantly fluctuated after ice-snow disaster in 2008, litter leaf stoichiometric traits indicated that litter leaf chemistry showed more easily decomposition with higher C/P ratio, N/P ratio, and lower C/N ratio. It is clear from this study that litterfall restoration dynamic would result in long-term changes in litter nutrient cycling and may help predicting below ground carbon dynamic in future research as well as subtropical forest inventories following extreme disturbance. Xiaogai Ge, Benzhi Zhou, and Yilin Tang Copyright © 2014 Xiaogai Ge et al. All rights reserved. Source Allocation of Long-Range Asian Dusts Transportation across the Taiwan Strait by Innovative Chemical-Assisted Identification Methods Wed, 27 Aug 2014 00:00:00 +0000 This study used the backward trajectory calculation to obtain the transportation routes of Asian dusts and further combined the chemical composition with the enrichment factor (EF) and the grey relational analysis (GR) to identify the potential sources of eighteen Asian dust storm (ADS) events. The results showed that the chemical compositions of atmospheric particles sampled at the Pescadores Islands were very similar to source soils fugitively emitted from Inner Mongolia, which could assist in identifying the source regions of Asian dusts. This study further compared the source allocation of Asian dusts obtained from EF, GR, and backward trajectory, which showed that the source regions of Asian dusts obtained from these three methods were quite similar. The similarity of backward trajectory and GR reached as high as 83.3%. Moreover, the similarity of backward trajectory calculation and EF or GR was up to 77.8% while that of the GR and EF was up to 83.3%. Overall, these three methods can successfully allocate the source regions of Asian dusts by 66.7%. Moreover, these innovative chemical-assisted methods can be successfully applied to identify the source regions of Asian dusts for 18 ADS events. Yi-Hsiu Jen, Yi-Chi Liu, Iau-Ren Ie, Chung-Shin Yuan, and Chung-Hsuang Hung Copyright © 2014 Yi-Hsiu Jen et al. All rights reserved. Uncertainty Assessment: Reservoir Inflow Forecasting with Ensemble Precipitation Forecasts and HEC-HMS Wed, 27 Aug 2014 00:00:00 +0000 During an extreme event, having accurate inflow forecasting with enough lead time helps reservoir operators decrease the impact of floods downstream. Furthermore, being able to efficiently operate reservoirs could help maximize flood protection while saving water for drier times of the year. This study combines ensemble quantitative precipitation forecasts and a hydrological model to provide a 3-day reservoir inflow in the Shihmen Reservoir, Taiwan. A total of six historical typhoons were used for model calibration, validation, and application. An understanding of cascaded uncertainties from the numerical weather model through the hydrological model is necessary for a better use for forecasting. This study thus conducted an assessment of forecast uncertainty on magnitude and timing of peak and cumulative inflows. It found that using the ensemble-mean had less uncertainty than randomly selecting individual member. The inflow forecasts with shorter length of cumulative time had a higher uncertainty. The results showed that using the ensemble precipitation forecasts with the hydrological model would have the advantage of extra lead time and serve as a valuable reference for operating reservoirs. Sheng-Chi Yang and Tsun-Hua Yang Copyright © 2014 Sheng-Chi Yang and Tsun-Hua Yang. All rights reserved.