Advances in Meteorology The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Recent Changes in the Annual Mean Regional Hadley Circulation and Their Impacts on South America Sun, 22 Nov 2015 12:31:57 +0000 This work employs the regional climate model RegCM4 and observational datasets to investigate the impacts of changes in the intensity and poleward edge of regional HC over South America (HCSA) on the patterns of wind, geopotential height, precipitation, and temperature during the period 1996–2011. Significant trends of HCSA intensification and poleward expansion are found during the period analyzed. To evaluate the effects of these changes over SA, two composites, representing the intensification and poleward expansion cases, are examined separately. Significant correlations are seen between the temperature, zonal wind, and the HCSA intensity over the northern, central, and southern regions of SA and South Atlantic. Results show that, in both composites, regions with anomalous easterly (westerly) winds coming from (towards) the Atlantic Ocean have negative (positive) correlations with the HCSA intensity and poleward edge. The model performance varies regionally and the southern SA region exhibits better agreement with the observations. The role of the sea surface temperatures in driving the changes in the HCSA is examined. Notable similarity is found in the results for the two cases analyzed, which could indicate that, in most cases, the changes in the intensity and poleward edge of the HCSA are occurring simultaneously. Ana Carolina Vasques Freitas and Tércio Ambrizzi Copyright © 2015 Ana Carolina Vasques Freitas and Tércio Ambrizzi. All rights reserved. Hydrograph Separation in the Headwaters of the Shule River Basin: Combining Water Chemistry and Stable Isotopes Sun, 22 Nov 2015 12:23:02 +0000 The runoff components were identified in the headwater area of Shule River Basin, using isotopic and chemical tracing with particular focus on the temporal variations of catchment sources. A total of 95 samples, including precipitation, groundwater, and glacial meltwater, were collected and analyzed for stable water isotopes (18O and 2H) and major chemical ion parameters (potassium, sodium, calcium, magnesium, sulfate, chloride, and bicarbonate). Based on the isotope and water chemistry data, we applied end member mixing analysis (EMMA) to identify and quantify the major runoff generating sources and their contributions. The contributions of groundwater, precipitation, and glacial meltwater were 66.7%, 19.9%, and 13.4%, respectively. The study indicated that groundwater dominated runoff in the headwater area of Shule River Basin. The roles of glacier meltwater should be remarkable in water resource management in this basin. The uncertainties of the EMMA method were summarized and estimated via a classical Gaussian error propagation technique. Analyses suggested that the uncertainty in the measurement method was less important than that in the temporal and spatial variations of tracer concentrations. The uncertainty was sensitive when the difference between mixing components was small. Therefore, the variation of tracers and the difference of mixing components should be considered when hydrograph separation was applied in the basin. Jiaxin Zhou, Jinkui Wu, Shiwei Liu, Guoxiong Zeng, Jia Qin, Xiuna Wang, and Qiudong Zhao Copyright © 2015 Jiaxin Zhou et al. All rights reserved. Northern Hemisphere Climatology and Interannual Variability of Storm Tracks in NCEP’s CFS Model Sun, 22 Nov 2015 12:05:13 +0000 Evaluating the climatology and interannual variability of storm tracks in climate models represents an excellent way to evaluate their ability to simulate synoptic-scale phenomena. We generate storm tracks from the National Center for Environmental Prediction (NCEP) Climate Forecast System (CFS) model for the northern hemisphere (NH) and compare them to storm tracks generated from NCEP’s reanalysis I data, the European Centre for Medium Range Prediction (ECMWF) ERA40 data, and CFS reanalysis data. To assess interannual variability, we analyze the impacts of El Niño, the North Atlantic Oscillation (NAO), and the Indian Ocean Dipole (IOD). We show that the CFS model is capable of simulating realistic storm tracks for frequency and intensity in the NH. The CFS storm tracks exhibit a reasonable response to El Niño and the NAO. However, it did not capture interannual variability for the IOD. Since one path by which storm tracks respond to external forcing is via Rossby waves due to anomalous heating, the CFS model may not be able to capture this effect especially since anomalous heating for the IOD is more local than El Niño. Our assessment is that the CFS model’s storm track response is sensitive to the strength of external forcing. Timothy Paul Eichler, Francisco Alvarez, and Jon Gottschalck Copyright © 2015 Timothy Paul Eichler et al. All rights reserved. Actual Evapotranspiration in Suli Alpine Meadow in Northeastern Edge of Qinghai-Tibet Plateau, China Sun, 22 Nov 2015 09:58:58 +0000 Actual evapotranspiration was observed by using eddy covariance (EC) technique, calculated by micrometeorological method the Bowen ratio energy balance (BREB) and measured by micro-lysimeter (ML) in the Suli alpine meadow which located in the northeastern edge of Qinghai-Tibet Plateau noted for its high elevation and cold environment during the growing season in 2011. Results showed that the energy balance ratio for half-hour data was 0.74. Without consideration of uncertainty, the evapotranspiration values estimated by BREB, ML, and EC were 270.6 mm, 238.9 mm, and 236.1 mm, respectively. Significant correlation existed between the evapotranspiration results by the three methods. Uncertainties of the evapotranspiration estimation by BREB, ML, and EC were 19.6 mm, 15.6 mm, and 15.1 mm, respectively. Deduced by facts on the natural and vegetation conditions, the value of evapotranspiration should be equal to that of precipitation, that is, about 252 mm. From this point, the evapotranspiration values estimated by the three methods were within a reliable range. The EC method has larger advantage and wider scope for the estimation of evapotranspiration in alpine meadow area. Jin-kui Wu, Shi-qiang Zhang, Hao Wu, Shi-wei Liu, Yu Qin, and Jia Qin Copyright © 2015 Jin-kui Wu et al. All rights reserved. Contribution of River Mouth Reach to Sediment Load of the Yangtze River Tue, 17 Nov 2015 07:10:59 +0000 This paper examined the sediment gain and loss in the river mouth reach of the Yangtze River by considering sediment load from the local tributaries, erosion/accretion of the river course, impacts of sand mining, and water extraction. A quantitative estimation of the contribution of the river mouth reach to the sediment load of the Yangtze River was conducted before and after impoundment of the Three Gorges Dam (TGD) in 2003. The results showed that a net sediment load loss of 1.78 million ton/yr (Mt/yr) occurred from 1965 to 2002 in the study area. The contribution of this reach to the sediment discharge into the sea is not as high as what was expected before the TGD. With impoundment of the TGD, channel deposition (29.90 Mt/yr) and a net sediment loss of 30.89 Mt/yr occurred in the river mouth reach from 2003 to 2012. The river mouth reach has acted as a sink but not a source of sediment since impoundment of the TGD, which has exacerbated the decrease in sediment load. Technologies should be advanced to measure changes in river channel morphology, as well as in water and sediment discharges at the river mouth reach. C. Wang, S. B. Dai, L. S. Ran, L. Jiang, and W. T. Li Copyright © 2015 C. Wang et al. All rights reserved. Millennial-Scale Asian Monsoon Influenced Longjie Lake Evolution during Marine Isotope Stage 3, Upper Stream of Changjiang (Yangtze) River, China Tue, 17 Nov 2015 06:31:35 +0000 Millennial-scale climate change in Asian monsoon region during MIS 3 has been studied using stalagmite, loess, and peat sediments. However, records from more materials are essential to further illustrate dynamics of these events. In the present study, a time-series of grain size covering 60–30 ka was reconstructed from lake sediments in the Yunnan Province, southwestern China. The time-series contains 14 obvious millennial-scale events during the period. On millennial-scale, the grain size record is generally consistent with mean stalagmite δ18O from Hulu Cave, grain size of Gulang loess sequence, Chinese Loess Plateau, and Greenland ice core δ18O. The results show that the millennial-scale variation was well compared with the Dansgaard-Oeschger (DO) events, indicating that those global events were well documented in lake sediments in the Asian monsoon region. Because the grain size can be used as a proxy for water discharge, we suggest that signal of the DO events might be transmitted to lake evolution by Asian monsoon. Chaozhu Li, Jianli Fu, Liang Yi, Xin Zhou, Shubing Wang, and Fuchu Jiang Copyright © 2015 Chaozhu Li et al. All rights reserved. Flooding Regime Impacts on Radiation, Evapotranspiration, and Latent Energy Fluxes over Groundwater-Dependent Riparian Cottonwood and Saltcedar Forests Mon, 16 Nov 2015 13:51:47 +0000 Radiation and energy balances are key drivers of ecosystem water and carbon cycling. This study reports on ten years of eddy covariance measurements over groundwater-dependent ecosystems (GDEs) in New Mexico, USA, to compare the role of drought and flooding on radiation, water, and energy budgets of forests differing in species composition (native cottonwood versus nonnative saltcedar) and flooding regime. After net radiation (700–800 W m−2), latent heat flux was the largest energy flux, with annual values of evapotranspiration exceeding annual precipitation by 250–600%. Evaporative cooling dominated the energy fluxes of both forest types, although cottonwood generated much lower daily values of sensible heat flux (<−5 MJ m−2 d−1). Drought caused a reduction in evaporative cooling, especially in the saltcedar sites where evapotranspiration was also reduced, but without a substantial decline in depth-to-groundwater. Our findings have broad implications on water security and the management of native and nonnative vegetation within semiarid southwestern North America. Specifically, consideration of the energy budgets of GDEs as they respond to fluctuations in climatic conditions can inform the management options for reducing evapotranspiration and maintaining in-stream flow, which is legally mandated as part of interstate and international water resources agreements. James Cleverly, James R. Thibault, Stephen B. Teet, Paul Tashjian, Lawrence E. Hipps, Clifford N. Dahm, and Derek Eamus Copyright © 2015 James Cleverly et al. All rights reserved. Climate Change Impact on the Hydrology of a Typical Watershed in the Tianshan Mountains Sun, 15 Nov 2015 13:59:15 +0000 To study the impact of future climatic changes on hydrology in the Kaidu River Basin in the Tianshan Mountains, two sets of future climatic data were used to force a well-calibrated hydrologic model: one is bias-corrected regional climate model (RCM) outputs for RCP4.5 and RCP8.5 future emission scenarios, and the other is simple climate change (SCC) with absolute temperature change of −1~6°C and relative precipitation change of −20%~60%. Results show the following: (1) temperature is likely to increase by 2.2°C and 4.6°C by the end of the 21st century under RCP4.5 and RCP8.5, respectively, while precipitation will increase by 2%~24%, with a significant rise in the dry season and small change in the wet season; (2) flow will change by −1%~20%, while evapotranspiration will increase by 2%~24%; (3) flow increases almost linearly with precipitation, while its response to temperature depends on the magnitude of temperature change and flow decrease is significant when temperature increase is greater than 2°C; (4) similar results were obtained for simulations with RCM outputs and with SCC for mild climate change conditions, while results were significantly different for intense climate change conditions. Gonghuan Fang, Jing Yang, Yaning Chen, Shuhua Zhang, Haijun Deng, Haimeng Liu, and Philippe De Maeyer Copyright © 2015 Gonghuan Fang et al. All rights reserved. Impacts of Climate Change and Human Activities on Runoff and Sediment Load of the Xiliugou Basin in the Upper Yellow River Tue, 10 Nov 2015 07:20:55 +0000 Using data of temperature, wind, precipitation, water discharge, and sediment load, the changes in runoff and sediment load of the Xiliugou basin in the upper Yellow River were investigated and the contributions of climate change and human activities to these changes were quantitatively estimated. Results show that the runoff and sediment load of the stream declined gradually in 1960–2012. According to the abrupt change point detected, the runoff and sediment series were divided into two periods: 1960–1998 and 1999–2012. The reductions of runoff and sediment load in 1999–2012 were found to be related to climate change and human activities, and the latter played a dominant role with a contribution of about 68% and 75%, respectively. The effects of rainfall intensity should be considered to avoid overestimating or underestimating the contributions of rainfall changes to the variations of runoff and sediment load in the semiarid region. An inspection of changes in water discharge and sediment regime indicated that the frequency of discharge between 0 and 5 m3/s increased while that between 5 and 1000 m3/s decreased in 2006–2012. This phenomenon can be attributed principally to the soil and water conservation practices. Haifang Yao, Changxing Shi, Wenwei Shao, Jianbin Bai, and Hui Yang Copyright © 2015 Haifang Yao et al. All rights reserved. A Dynamic Analysis of a Record Breaking Winter Season Blocking Event Tue, 10 Nov 2015 07:01:16 +0000 The objective of this work is to study in detail a strong North Pacific, large amplitude, and long-lived blocking event that occurred during January 23–February 16, 2014. Indeed, it was the 11th strongest Northern Hemisphere event lasting longer than 20 days since 1968. This event formed out of the strong ridge that was associated with the devastating drought in the Western United States during the winter season of 2013-2014. This blocking event had many outstanding dynamical characteristics, the chief of which was that it survived an abrupt change in the planetary-scale flow when the Pacific North American pattern index changed from positive to negative in early February. The block then reintensified and persisted into mid-February. Several diagnostic techniques are employed to investigate the change in the planetary-scale flow during early February 2014 that have been applied to blocking before but aren’t as well known in the blocking literature. Andrew D. Jensen Copyright © 2015 Andrew D. Jensen. All rights reserved. The Impact of Trends in the Large Scale Atmospheric Circulation on Mediterranean Surface Turbulent Heat Fluxes Mon, 09 Nov 2015 12:12:15 +0000 Interannual variations of latent heat fluxes (LHF) and sensible heat fluxes (SHF) over the Mediterranean for the boreal winter season (DJF) show positive trends during 1958–2011. Using reanalysis and satellite-based products, the variability and trends in the heat fluxes are compared with variations in three atmospheric teleconnection patterns: the North Atlantic Oscillation (NAO), the pressure and position of the Azores High (AH), and the East Atlantic-West Russia teleconnection pattern (EAWR). Comparison of correlations between the heat fluxes and teleconnections, along with analysis of composites of surface temperature, humidity, and wind fields for different teleconnection states, demonstrates that the AH explains the heat flux changes more successfully than NAO and EAWR. Trends in pressure and longitude of the Azores High show a strengthening and an eastward shift. Variations of the Azores High occur along an axis defined by lower pressure and westward location at one extreme and higher pressure and eastward location at the other extreme. The shift of the AH from predominance of the low/west state to the high/east state induces trends in Mediterranean Sea surface winds, temperature, and moisture. These, combined with sea surface warming trends, produce trends in wintertime sensible and latent heat fluxes. Joy Romanski and Sultan Hameed Copyright © 2015 Joy Romanski and Sultan Hameed. All rights reserved. Surface Albedo Variation and Its Influencing Factors over Dongkemadi Glacier, Central Tibetan Plateau Sun, 08 Nov 2015 13:38:09 +0000 Glacier albedo plays a critical role in surface-atmosphere energy exchange, the variability of which influences glacier mass balance as well as water resources. Dongkemadi glacier in central Tibetan Plateau was selected as study area; this research used field measurements to verify Landsat TM-derived albedo and MOD10A1 albedo product and then analyzed the spatiotemporal variability of albedo over the glacier according to them, as well as its influence factors and the relationship with glacier mass balance. The spatial distribution of glacier albedo in winter did not vary with altitude and was determined by terrain shield, whereas, in summer, albedo increased with altitude and was only influenced by terrain shield at accumulation zone. During 2000–2009, albedo in summer decreased at a rate of 0.0052 per year and was influenced by air temperature and precipitation levels, whereas albedo in winter increased at a rate of 0.0045 per year, influenced by the level and frequency of precipitation. The annual variation of albedo in summer during 2000–2012 has the high relative to that of glacier mass balance measurement, which indicates that glacier albedo in the ablation period can be considered as a proxy for glacier mass balance. Jie Wang, Yuhuan Cui, Xiaobo He, Jian Zhang, and Shijiang Yan Copyright © 2015 Jie Wang et al. All rights reserved. Hydrologic Responses to Land Use Change in the Loess Plateau: Case Study in the Upper Fenhe River Watershed Thu, 05 Nov 2015 09:20:52 +0000 We applied an integrated approach to investigate the impacts of land use and land cover (LULC) changes on hydrology at different scales in the Loess Plateau of China. Hydrological modeling was conducted for the LULC maps from remote sensing images at two times in the Upper Fenhe River watershed using the SWAT model. The main LULC changes in this watershed from 1995 to 2010 were the transformation of farmland into forests, grassland, and built-up land. The simulation results showed that forested land contributed more than any other LULC class to water yield, but built-up land had most impact due to small initial loss and infiltration. At basin scale, a comparison of the simulated hydrological components of two LULC maps showed that there were slight increases in average annual potential evapotranspiration, actual evapotranspiration, and water yield, but soil water decreased, between the two intervals. In subbasins, obvious LULC changes did not have clear impacts on hydrology, and the impacts may be affected by precipitation conditions. By linking a hydrological model to remote sensing image analysis, our approach of quantifying the impacts of LULC changes on hydrology at different scales provide quantitative information for stakeholders in making decisions for land and water resource management. Zhixiang Lu, Songbing Zou, Zuodong Qin, Yonggang Yang, Honglang Xiao, Yongping Wei, Kai Zhang, and Jiali Xie Copyright © 2015 Zhixiang Lu et al. All rights reserved. Evaluation of Water Storage Change of Inland Cryosphere in Northwestern China Thu, 05 Nov 2015 09:07:06 +0000 The Gravity Recovery and Climate Experiment (GRACE) satellite mission provides measurements of Earth’s static and time-variable gravity fields with monthly resolution. In this study, changes of water storage in northwestern China were determined by GRACE monthly gravity field data obtained from 2003 to 2010. Comparisons of water storage change (WSC) simulated by a four-dimensional assimilation model (Noah) and observed by GRACE revealed similar patterns of change and a correlation coefficient of 0.71 . Trend analysis indicated significant changes in the spatiotemporal variation of WSC in northwestern China during the 8-year study period, which were stronger in the east than in the west and more pronounced in the south than in the north. The most pronounced increase in water storage occurred in Gansu and Qinghai provinces, but, overall, water storage increased by 0.61 mm/a over northwestern China during the study period. Clear seasonal variations of WSC and precipitation were found, because glacial meltwater and precipitation are the main sources of water in the hydrosphere; meanwhile, the distributions of glaciers and permafrost also affect the spatial distribution of WSC. Min Xu, Shichang Kang, and Jiazhen Li Copyright © 2015 Min Xu et al. All rights reserved. Comparison of Stationary and Dynamic Conceptual Models in a Mountainous and Data-Sparse Catchment in the South-Central Chilean Andes Mon, 02 Nov 2015 07:50:10 +0000 In recent years, it has been documented that climatic variability influences hydrological processes; however, these influences, such as hydrologic dynamics, have not yet been incorporated into models, which have been assumed as stationary with regard to climatic conditions. In this study, the temporal variability of hydrological processes and their influence on the water balance of a mountainous and data-sparse catchment in Chile are observed and modeled through the comparison of a stationary (time-invariant parameters) and dynamic (time-variant parameters) model. Since conceptual models are the most adequate option for a data-scarce basin, a conceptual model integrated with the Monte Carlo Analysis Toolbox is used to perform the analyses. Simple analyses aimed at increasing the amount of information obtained from models were used. The General and Dynamic Identifiability Analyses were used to perform stationary and dynamic calibration strategies, respectively. As a result we concluded that the dynamic model is more robust than the stationary one. Additionally, DYNIA helped us to observe the temporal variability of hydrological processes. This analysis contributed to a better understanding of hydrological processes in a data-sparse Andean catchment and thus could potentially help reduce uncertainties in the outputs of hydrological models under scenarios of climate change and/or variability. Camila Toledo, Enrique Muñoz, and Mauricio Zambrano-Bigiarini Copyright © 2015 Camila Toledo et al. All rights reserved. Observations and Modeling of the Climatic Impact of Land-Use Changes 2014 Sun, 01 Nov 2015 09:19:55 +0000 Xiangzheng Deng, R. B. Singh, Qun’ou Jiang, Jinwei Dong, and Hongbo Su Copyright © 2015 Xiangzheng Deng et al. All rights reserved. Validation of the Accuracy of Different Precipitation Datasets over Tianshan Mountainous Area Wed, 28 Oct 2015 08:29:33 +0000 Precipitation is one of the important water supplies in the arid and semiarid regions of northwestern China, playing a vital role in maintaining the fragile ecosystem. In remote mountainous area, it is difficult to obtain an accurate and reliable spatialization of the precipitation amount at the regional scale due to the inaccessibility, the sparsity of observation stations, and the complexity of relationships between precipitation and topography. Furthermore, accurate precipitation is important driven data for hydrological models to assess the water balance and water resource for hydrologists. Therefore, the use of satellite remote sensing becomes an important means over mountainous area. Precipitation datasets based on station data or pure satellite data have been increasingly available in spite of several weaknesses. This paper evaluates the usefulness of three precipitation datasets including TRMM 3B43_V6, 3B43_V7, and Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation with rain gauge data over Tianshan mountainous area where precipitation data is scarce. The results suggest that precipitation measurements only provided accurate information on a small scale, while the satellite remote sensing of precipitation had obvious advantages in basin scale or large scale especially over remote mountainous area. Chuancheng Zhao, Shuxia Yao, Shiqiang Zhang, Haidong Han, Qiudong Zhao, and Shuhua Yi Copyright © 2015 Chuancheng Zhao et al. All rights reserved. Impacts of Land Use Change on the Regional Climate: A Structural Equation Modeling Study in Southern China Wed, 28 Oct 2015 07:14:35 +0000 With the frequent human activities operating on the earth, the impacts of land use change on the regional climate are increasingly perceptible. Under the background of the rapid urbanization, understanding the impacts of land use change on the regional climate change is vital and significant. In this study, we investigated the relationships between land use change and regional climate change through a structural equation model. Southern China was selected as the study area for its rapid urbanization and different structure of land use among its counties. The results indicate that the path coefficients of “vegetation,” “Urban and surrounding area,” and “other” to “climate” are −0.42, 0.20, and 0.46, respectively. Adding vegetation area is the main method to mitigate regional climate change. Urban and surrounding area and other areas influence regional climate by increasing temperature and precipitation to a certain extent. Adding grassland and forestry, restraining sprawl of built-up area, and making the most use of unused land are efficient ways to mitigate the regional climate change in Southern China. The results can provide feasible recommendations to land use policy maker. Zhanqi Wang, Bingqing Li, and Jun Yang Copyright © 2015 Zhanqi Wang et al. All rights reserved. Groundwater—Surface Water Interactions in a Mountain-to-Coast Watershed: Effects of Climate Change and Human Stressors Mon, 26 Oct 2015 08:08:36 +0000 Watersheds located within a mountain to coast physiographic setting have been described as having a highly interconnected surface water and groundwater environment. The quantification of groundwater—surface water interactions at the watershed scale requires upscaling. This study uses MIKE SHE, a coupled numerical model, to explore the seasonally and spatially dynamic nature of these interactions in the Cowichan Watershed on Vancouver Island, British Columbia, Canada. The calibrated model simulates a transition of the Cowichan River from mostly gaining within the valley, to losing stream near the coast where groundwater extraction is focused. Losing and gaining sections correlate with geological substrate. Recharge across the watershed accounts for 17% of precipitation. Climate change is projected to lessen snowpack accumulation in the high alpine and alter timing of snowmelt, resulting in higher spring and winter river discharge and lower summer flows. S. B. Foster and D. M. Allen Copyright © 2015 S. B. Foster and D. M. Allen. All rights reserved. The Effects of Climate Change on Variability of the Growing Seasons in the Elbe River Lowland, Czech Republic Sun, 25 Oct 2015 13:18:09 +0000 This research aimed to identify an approach for adaptation of agriculture to increased climate variability and projected changes, taking into account regional specificity of climate change. Changes in the timing of growing season (GS) parameters for both observation and models data were computed using daily mean temperatures for three thresholds that correspond to the physiological requirements of the vegetable types. This research included a new assessment of the potential impacts of climate change on the GS of vegetables grown in the Elbe River lowland, one of the largest farmed vegetable regions in Central Europe. To accomplish this, a comprehensive analysis was conducted of the spatiotemporal variability of the date of the beginning of the growing season (BGS), the date of the end of the growing season (EGS), and the length of the growing season (GSL) for the period 1961–2011. In addition, an assessment was made of the potential changes in the dates of the BGS, EGS, and GSL for the Elbe River lowland, simulated using the regional climate models. Prospective areas for growing thermophilic vegetables in the study region were also determined. Vera Potopová, Pavel Zahradníček, Luboš Türkott, Petr Štěpánek, and Josef Soukup Copyright © 2015 Vera Potopová et al. All rights reserved. Impact of Urbanization and Land-Use Change on Surface Climate in Middle and Lower Reaches of the Yangtze River, 1988–2008 Wed, 21 Oct 2015 11:56:47 +0000 Land-use/land cover change (LUCC) is one of the fundamental causes of global environmental change. In recent years, understanding the regional climate impact of LUCC has become a hot-discussed topic worldwide. Some studies have explored LUCC impact on regional climate in specific cities, provinces, or farming areas. However, the quick-urbanized areas, which are highly influenced by human activities, have the most severe land-use changes in developing countries, and their climatic impact cannot be ignored. This study aims to identify the impact of land-use change coupled with urbanization on regional temperature and precipitation in the metropolitan areas of middle and lower reaches of the Yangtze River in China by means of spatial analysis and numeric methods. Based on the exploration of land-use change and climate change during 1988–2008, the impact of land-use transition from non-built-up area to built-up area on temperature and precipitation was analyzed. The results indicated that the land-use conversion has affected the regional temperature with an increasing effect in the study area, while the influence on precipitation was not so significant. The results can provide useful information for spatial planning policies in consideration of regional climate change. Xiaowei Yao, Zhanqi Wang, and Hua Wang Copyright © 2015 Xiaowei Yao et al. All rights reserved. Impacts of Two-Type ENSO on Rainfall over Taiwan Tue, 20 Oct 2015 12:16:30 +0000 Impacts of two-type ENSO (El Niño/Southern Oscillation), canonical ENSO and ENSO Modoki, on rainfall over Taiwan are investigated by the monthly mean rainfall data accessed from Taiwan Central Weather Bureau. The periods of the two-type ENSO are distinguished by Niño 3.4 index and ENSO Modoki index (EMI). The rainfall data in variously geographical regions are analyzed with the values of Niño 3.4 and EMI by correlation method. Results show that the seasonal rainfalls over Taiwan are different depending on the effects of two-type ENSO. In canonical El Niño episode, the rainfall increases in winter and spring while it reduces in summer and autumn. On the contrary, the rainfall increases in summer and autumn but reduces in winter and spring in El Niño Modoki episode. Nevertheless, two types of La Niña cause similar effects on the rainfall over Taiwan. It increases in autumn only. The rainfall variations in different types of ENSO are mainly caused by the monsoon and topography. Chen-Chih Lin, Yi-Jiun Liou, and Shih-Jen Huang Copyright © 2015 Chen-Chih Lin et al. All rights reserved. Modeling the Effects of Land-Cover Change on Rainfall-Runoff Relationships in a Semiarid, Eastern Mediterranean Watershed Tue, 20 Oct 2015 11:49:34 +0000 Temporal changes and spatial patterns are often studied by analyzing land-cover changes (LCCs) using spaceborne images. LCC is an important factor, affecting runoff within watersheds. The objective was to estimate the effects of 20 years of LCCs on rainfall-runoff relations in an extreme rainfall event. A 1989 Landsat TM-derived classification map was used as input for a Kinematic Runoff and Erosion (KINEROS) hydrological model along with the precipitation data of an extreme rainfall event. Model calibration was performed using measured runoff volume data. Validation of the model performance was conducted by comparing the model results to measured data. A similar procedure was used with a 2009 land-cover classification map as an input to the KINEROS model, along with similar precipitation data and calibration parameters, in order to understand the possible outcomes of a rainfall event of such a magnitude and duration after 20 years of LCCs. The results show an increase in runoff volume and peak discharge between the time periods as a result of LCCs. A strong relationship was detected between vegetation cover and the runoff volume. The LCCs with most pronounced effects on runoff volumes were related to urbanization and vegetation removal. Noa Ohana-Levi, Arnon Karnieli, Roey Egozi, Amir Givati, and Aviva Peeters Copyright © 2015 Noa Ohana-Levi et al. All rights reserved. Scenario-Based Impact Assessment of Land Use/Cover and Climate Changes on Watershed Hydrology in Heihe River Basin of Northwest China Sun, 18 Oct 2015 09:08:47 +0000 This study evaluated hydrological impacts of potential climate and land use changes in Heihe River Basin of Northwest China. The future climate data for the simulation with Soil and Water Assessment Tool (SWAT) were prepared using a dynamical downscaling method. The future land uses were simulated with the Dynamic Land Use System (DLS) model by establishing Multinomial Logistic Regression (MNL) model for six land use types. In 2006–2030, land uses in the basin will experience a significant change with a prominent increase in urban areas, a moderate increase in grassland, and a great decrease in unused land. Besides, the simulation results showed that in comparison to those during 1981–2005 the temperature and precipitation during 2006–2030 will change by +0.8°C and +10.8%, respectively. The land use change and climate change will jointly make the water yield change by +8.5%, while they will separately make the water yield change by −1.8% and +9.8%, respectively. The predicted large increase in future precipitation and the corresponding decrease in unused land will have substantial impacts on the watershed hydrology, especially on the surface runoff and streamflow. Therefore, to mitigate negative hydrological impacts and utilize positive impacts, both land use and climate changes should be considered in water resource planning for the Heihe River Basin. Feng Wu, Jinyan Zhan, Hongbo Su, Haiming Yan, and Enjun Ma Copyright © 2015 Feng Wu et al. All rights reserved. The Elements of Water Balance in the Changing Climate in Poland Tue, 13 Oct 2015 07:39:17 +0000 Strong global warming has been observed in the last three decades. Central Europe, including Poland, is not an exception. Moreover, climate projections for Poland foresee further warming as well as changes in the spatial and seasonal distribution and quantity of precipitation. However, climate models do not agree on the sign of change of precipitation. In Poland precipitation is projected to decrease in summer (this finding is not robust, being model-dependent) and to increase in winter. Therefore, there is still considerable uncertainty regarding likely climate change impacts on water resources in Poland. However, there is no doubt that changes in the thermal characteristics as well as in precipitation will influence changes in the water balance of the country. In this study, the components of climatic water balance, that is, precipitation, evaporation, and runoff, are calculated for the average conditions in the control period of 1961–1990 and in the future (2071–2100) in Poland. The changes of the water balance components for the present and for the future are compared and analysed. Due to insufficient consistency between climate models a possible range of changes should be presented; hence the multimodel projections from ENSEMBLES Project of the European Union are used in this study. Małgorzata Szwed Copyright © 2015 Małgorzata Szwed. All rights reserved. Hydrologic Variations and Stochastic Modeling of Runoff in Zoige Wetland in the Eastern Tibetan Plateau Mon, 12 Oct 2015 11:52:38 +0000 Hydrological time series data (1988–2008) of the Hei River, the main water source to Zoige wetland in the Eastern Tibetan Plateau, were investigated. Results showed that the runoff distribution of Hei River varies with the relative change in amplitude () and the absolute change in amplitude ( m3/s) during the year. There was a significant decreasing trend since 1988 with annual runoff of 20.0 m3/s (1988–1994), 19.0 m3/s (1995–2000), and 15.2 m3/s (2001–2008). There were double peaks in runoff during the water year: the highest peak in the period of 1988–2000 occurred in July while in the period of 2001–2008 it occurred in October. Shifting peak flow means less water quantity in wetland during growing season. Nearest neighbor bootstrapping regressive method was used to predict daily runoff of the Hei River. Model results show that it was fitted with 94.23% of for daily time series, which can provide a basis for the development and utilization of regional water resources. Guanghua Qin, Hongxia Li, Zejiang Zhou, Kechao Song, and Li Zhang Copyright © 2015 Guanghua Qin et al. All rights reserved. Serial Analysis of Ten Precipitation-Based Indices by Land Use in Semiarid Regions Mon, 12 Oct 2015 11:49:12 +0000 Open ecosystems in Mexico are under increasing pressure, due particularly to the expansion of cities and agricultural activities. These developments occur without integrating biodiversity concerns in land use planning and result in extensive fragmentation and transformation of the landscapes. The semiarid region of Mesa Central was characterized using ten precipitation-based indices. Using multivariate statistical and geostatistical spatial analysis techniques, the influence of those indices on five land use strata was explored. Land use analysis indicated that the maximum values of the five significant precipitation-based indices were found in Grasslands, Agricultural Use, and Shrubs; minimum values were characteristic of substrates Secondary Desert Vegetation and Other Use. Our results suggest that the greatest number of extreme precipitation events is likely to occur in open ecosystems and consequently will have a strong influence on landscaping and land use. The semivariogram analysis and geostatistical layers demand attention from research institutions, policy makers, researchers, and food producers to take the appropriate and coordinated actions to propose scenarios to deal with climate change. Perhaps this study can stimulate thought concerning research endeavours aimed at promoting initiatives for biodiversity conservation and planning programs for climate change mitigation. Victor M. Rodríguez-Moreno, J. Ariel Ruíz-Corral, J. Saúl Padilla-Ramírez, Alfonso Peña-Ramos, and Thomas G. Kretzschmar Copyright © 2015 Victor M. Rodríguez-Moreno et al. All rights reserved. Comparison of Two Approaches for Estimating Precipitation Elasticity of Streamflow in China’s Main River Basins Sun, 11 Oct 2015 08:23:26 +0000 Two widely used approaches, nonparametric approach and Budyko framework approach, were used to calculate precipitation elasticity of streamflow () in China’s main river basins. While the Budyko framework illustrates only the effect of climate on , the nonparametric approach illustrates the effects of both climate and human activity on . Both approaches showed similar spatial pattern of , with high values for northern arid catchments and low values for southern humid catchments, suggesting high sensitivity of streamflow to climate in the arid catchments in China’s north. Inland catchments had low values, probably because most of the annual streamflow was driven by glacial and snowmelt. While strong anthropologic activities reduce the sensitivity of streamflow to precipitation in some northern arid catchments, which was indicated by lower values produced by nonparametric approach, the combined use of the two approaches underscored the significance in identifying the effects of anthropologic factors on streamflow. Xinyao Zhou, Yongqiang Zhang, and Yonghui Yang Copyright © 2015 Xinyao Zhou et al. All rights reserved. Interpolation of Missing Precipitation Data Using Kernel Estimations for Hydrologic Modeling Thu, 08 Oct 2015 08:14:42 +0000 Precipitation is the main factor that drives hydrologic modeling; therefore, missing precipitation data can cause malfunctions in hydrologic modeling. Although interpolation of missing precipitation data is recognized as an important research topic, only a few methods follow a regression approach. In this study, daily precipitation data were interpolated using five different kernel functions, namely, Epanechnikov, Quartic, Triweight, Tricube, and Cosine, to estimate missing precipitation data. This study also presents an assessment that compares estimation of missing precipitation data through th nearest neighborhood (NN) regression to the five different kernel estimations and their performance in simulating streamflow using the Soil Water Assessment Tool (SWAT) hydrologic model. The results show that the kernel approaches provide higher quality interpolation of precipitation data compared with the NN regression approach, in terms of both statistical data assessment and hydrologic modeling performance. Hyojin Lee and Kwangmin Kang Copyright © 2015 Hyojin Lee and Kwangmin Kang. All rights reserved. Effects of Climate Change and Human Activities on Surface Runoff in the Luan River Basin Wed, 07 Oct 2015 07:18:10 +0000 Quantifying the effects of climate change and human activities on runoff changes is the focus of climate change and hydrological research. This paper presents an integrated method employing the Budyko-based Fu model, hydrological modeling, and climate elasticity approaches to separate the effects of the two driving factors on surface runoff in the Luan River basin, China. The Budyko-based Fu model and the double mass curve method are used to analyze runoff changes during the period 1958~2009. Then two types of hydrological models (the distributed Soil and Water Assessment Tool model and the lumped SIMHYD model) and seven climate elasticity methods (including a nonparametric method and six Budyko-based methods) are applied to estimate the contributions of climate change and human activities to runoff change. The results show that all quantification methods are effective, and the results obtained by the nine methods are generally consistent. During the study period, the effects of climate change on runoff change accounted for 28.3~46.8% while those of human activities contributed with 53.2~71.7%, indicating that both factors have significant effects on the runoff decline in the basin, and that the effects of human activities are relatively stronger than those of climate change. Sidong Zeng, Chesheng Zhan, Fubao Sun, Hong Du, and Feiyu Wang Copyright © 2015 Sidong Zeng et al. All rights reserved.