{"title":"Evaluating and Modeling the Reliability of Continuous No-Rain Forecast from TIGGE Based on the First-Passage Problem and Fuzzy Mathematics","authors":"Chenkai Cai, Jianqun Wang, Zhijia Li, Xinyi Shen, Jinhua Wen, Helong Wang, Xinyan Zhou","doi":"10.1175/jhm-d-22-0126.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0126.1","url":null,"abstract":"\u0000As an important reference of reservoir regulation, more and more attention has been paid to the numeric precipitation forecast. Due to the uncertainty of meteorological prediction, reservoir regulation based on precipitation forecasts may lead to flood control risks. Therefore, the reliability of precipitation forecasts is crucial to the formulation of reservoir regulation strategy based on it. In this paper, a reliability assessment model for a continuous precipitation forecast is proposed based on the first-passage problem and fuzzy mathematics. The uncertainty of precipitation forecast is described by the generalized Bayesian model, and the fuzzy reliability of a continuous precipitation forecast can be obtained by the first-passage fuzzy probability model (FFPM). Due to the importance of a no-rain period in flood resource utilization, the no-rain forecasts from four different forecast centers in the Meishan basin are used as an example. The results show that the fuzzy mathematics is helpful in describing the uncertainty of the boundary for the no-rain set, and the fuzzy reliability of the no-rain forecast is affected by the selection of the range for the no-rain forecast, while the influence of the membership function is limited. Furthermore, due to the downward trend of fuzzy reliability as the lead time increases, there is a contradiction between excess water storage of the reservoir and the fuzzy reliability of the no-rain forecast. A longer continuous no-rain period means more excess water storage, but it also faces lower reliability. In actual reservoir regulation, the results of FFPM can be combined with more information to formulate better strategies for reservoir regulation.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81168055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Insights on Satellite-Based IMERG Precipitation Estimates at Multiple Space and Time Scales for a Developing Urban Region in India","authors":"Padmini Ponukumati, Azharuddin Mohammed, Satish Regonda","doi":"10.1175/jhm-d-22-0160.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0160.1","url":null,"abstract":"\u0000Satellite-based rainfall estimates are a great resource for data-scarce regions, including urban regions, because of its finer resolution. Integrated Multi-satellitE Retrievals for GPM (IMERG) is a widely used product and is evaluated at a city scale for the Hyderabad region using two different ground truths, i.e., India Meteorological Department (IMD) gridded rainfall and Telangana State Development Planning Society (TSDPS) automatic weather station (AWS) measured rainfall. The IMERG rainfall estimates are evaluated on multiple spatial and temporal scales as well as on a rainfall event scale. Both continuous and categorical verification metrics suggest good performance of IMERG on the daily scale; however, relatively decreased performance was observed on the hourly scale. Underestimated and overestimated IMERG estimates with respect to IMD gridded rainfall and AWS measured rainfall, respectively, suggest the performance depends on type of ground truth. Unlike categorical metrics, RMSE and PBIAS have a pattern implying a systematic error with respect to rainfall amount. Further, sample size, diurnal variations, and season are found to have a role in IMERG estimates’ performance. Temporal aggregation of hourly to daily time scales showed the improved IMERG performance; however, no spatial-scale dependence was observed among zonewise and Hyderabad region–wise rainfall estimates. Comparison of raw and bias-corrected IMERG rainfall-based intensity–duration–frequency (IDF) curves with corresponding hourly rain gauge IDF curves showcases the value addition via simple bias correction techniques. Overall, the study suggests the IMERG estimates can be used as an alternative data source, and it can be further improved by modifying the retrieval algorithm.\u0000\u0000\u0000Many urban regions are typically data sparse, which limits scientific understanding and reliable engineering designs of various urban hydrometeorology-relevant tasks, including climatological and extreme rainfall characterization, flood hazard assessment, and stormwater management systems. Satellite rainfall estimates come as a great resource and Integrated Multi-satellitE Retrievals for GPM (IMERG) acts as a best alternative. The Hyderabad region, the sixth-largest metropolitan area in India, is selected to analyze the widely used satellite estimates, i.e., retrievals for GPM. The study observed inaccuracies in the IMERG estimates that varied with rainfall magnitudes and space and time scales; nonetheless, the estimates can be used as an alternative data source for decision-making such as whether rain exceeds a certain threshold or not.\u0000","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80797450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Temporal and spatial amplification of extreme rainfall and extreme floods in a warmer climate","authors":"M. Faghih, F. Brissette","doi":"10.1175/jhm-d-22-0224.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0224.1","url":null,"abstract":"\u0000This work explores the relationship between catchment size, rainfall duration and future streamflow increases on 133 North American catchments with sizes ranging from 66.5 to 9886 km2. It uses the outputs from a high spatial (0.11°) and temporal (1-hour) resolution Single Model Initial condition Large Ensemble (SMILE) and a hydrological model to compute extreme rainfall and streamflow for durations ranging from 1 to 72 hours and for return periods of between 2 and 300 years. Increases in extreme precipitation are observed across all durations and return periods. The projected increases are strongly related to duration, frequency and catchment size, with the shortest durations, longest return periods and smaller catchments witnessing the largest relative rainfall increases. These increases can be quite significant, with the 100-year rainfall becoming up to 20 times more frequent over the smaller catchments. A similar duration-frequency-size pattern of increases is also observed for future extreme streamflow, but with even larger relative increases. These results imply that future increases in extreme rainfall will disproportionately impact smaller catchments, and particularly so for impervious urban catchments which are typically small, and whose stormwater drainage infrastructures are designed for long-return period flows, both being conditions for which the amplification of future flow will be maximized.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90345320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Currier, A. Wood, N. Mizukami, Bart Nijssen, J. Hamman, E. Gutmann
{"title":"Vegetation representation influences projected streamflow changes in the Colorado River Basin","authors":"W. Currier, A. Wood, N. Mizukami, Bart Nijssen, J. Hamman, E. Gutmann","doi":"10.1175/jhm-d-22-0143.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0143.1","url":null,"abstract":"\u0000Vegetation parameters for the Variable Infiltration Capacity (VIC) hydrologic model were recently updated using observations from the MODerate Resolution Imaging Spectroradiometer (MODIS). Previous work showed that these MODIS-based parameters improved VIC evapotranspiration simulations when compared to eddy covariance observations. Due to the importance of evapotranspiration within the Colorado River Basin, this study provided a basin-by-basin calibration of VIC soil parameters with updated MODIS-based vegetation parameters to improve streamflow simulations. Interestingly, while both configurations had similar historic streamflow performance, end-of-century hydrologic projections, driven by 29 downscaled global climate models under the RCP8.5 emissions scenario differed between the two configurations. The calibrated MODIS-based configuration had an ensemble mean that simulated little change in end-of-century annual streamflow volume (+0.4%) at Lees Ferry, AZ relative to the historical period (1960-2005). In contrast, the previous VIC configuration, which is used to inform decisions about future water resources in the Colorado River Basin projected an 11.7% decrease in annual streamflow. Both VIC configurations simulated similar amounts of evapotranspiration in the historical period. However, the MODIS-based VIC configuration did not show as much of an increase in evapotranspiration by the end of the century, primarily within the Upper Basin’s forested areas. Differences in evapotranspiration projections were the result of the MODIS-based vegetation parameters having lower leaf area index values and less forested area compared to previous vegetation estimates used in recent Colorado River Basin hydrologic projections. These results highlight the need to accurately characterize vegetation and better constrain climate sensitivities in hydrologic models.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82301474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Comparative Analysis of the Impact of Low-Level Jets and Atmospheric Rivers in the Central U.S.","authors":"Nabin Gyawali, C. Ferguson, L. Bosart","doi":"10.1175/jhm-d-22-0086.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0086.1","url":null,"abstract":"\u0000We present a comparative analysis of atmospheric rivers (ARs) and Great Plains low-level jets (GPLLJs) in the central U.S. during April–September 1901–2010 using ECMWF’s CERA-20C. The analysis is motivated by a perceived need to highlight overlap and synergistic opportunities between traditionally disconnected AR and GPLLJ research. First, using the Guan–Walliser integrated vapor transport (IVT)-based AR classification and Bonner–Whiteman-based GPLLJ classification, we identify days with either an AR and/or GPLLJ spanning 15% of the central U.S. These days are grouped into five event samples: 1) all GPLLJ, 2) AR GPLLJ, 3) non-AR GPLLJ, 4) AR non-GPLLJ, and 5) all AR. Then, we quantify differences in the frequency, seasonality, synoptic environment, and extreme weather impacts corresponding to each event sample. Over the 20th century, April–September AR frequency remained constant whereas GPLLJ frequency significantly decreased. Of GPLLJ days, 36% are associated with a coincident AR. Relative to ARs that are equally probable from April–September, GPLLJs exhibit distinct seasonality, with peak occurrence in July. A 500 hPa geopotential height comparison shows a persistent ridge over the central U.S for non-AR GPLLJ days, whereas on AR GPLLJ days, a trough and ridge pattern is present over western to eastern CONUS. AR GPLLJ days have 34% greater 850 hPa windspeeds, 53% greater IVT, and 72% greater 24-hour precipitation accumulation than non-AR GPLLJ days. In terms of 95th percentile 850 hPa windspeed, IVT, and 24-hour precipitation, that of AR GPLLJs is 25%, 45%, and 23% greater than non-AR GPLLJs, respectively.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87452595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Hurkmans, B. van den Hurk, M. Schmeits, F. Wetterhall, I. Pechlivanidis
{"title":"Seasonal streamflow forecasting for fresh water reservoir management in the Netherlands: an assessment of multiple prediction systems","authors":"R. Hurkmans, B. van den Hurk, M. Schmeits, F. Wetterhall, I. Pechlivanidis","doi":"10.1175/jhm-d-22-0107.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0107.1","url":null,"abstract":"\u0000For efficient management of the Dutch surface water reservoir Lake IJssel, (sub)seasonal forecasts of the water volumes going in and out of the reservoir are potentially of great interest. Here, streamflow forecasts were analyzed for the river Rhine at Lobith, which is partly routed through the river IJssel, the main influx into the reservoir. We analyzed seasonal forecast data sets derived from EFAS, E-HYPE and HTESSEL, which differ in their underlying hydrological formulation, but are all forced by meteorological forecasts from ECMWF SEAS5. We post-processed the streamflowforecasts using quantile mapping (QM) and analyzed several forecast quality metrics. Forecast performance was assessed based on the available reforecast period, as well as on individual summer seasons. QM increased forecast skill for nearly all metrics evaluated. Averaged over the reforecast period, forecasts were skillful for up to four months in spring, and early summer. Later in summer the skillful period deteriorated to 1-2 months. When investigating specific years with either low or high flow conditions, forecast skill increased with the extremity of the event. Although raw forecasts for both E-HYPE and EFAS were more skillful than HTESSEL, bias correction based on QM can significantly reduce the difference. In operational mode, the three forecast systems show comparable skill. In general, dry conditions can be forecasted with high success rates up to three months ahead, which is very promising for successful use of Rhine streamflow forecasts in downstream reservoir management.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83474246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yongliang Jiao, Ren Li, Tonghua Wu, Lin Zhao, Xiaodong Wu, Junjie Ma, Jimin Yao, G. Hu, Yao Xiao, Shuhua Yang, Wenhao Liu, Y. Qiao, Jianzong Shi, E. Du, Xiaofan Zhu, Shenning Wang
{"title":"Percentile-Based Relationship between Daily Precipitation and Surface Air Temperature over the Qinghai–Tibet Plateau","authors":"Yongliang Jiao, Ren Li, Tonghua Wu, Lin Zhao, Xiaodong Wu, Junjie Ma, Jimin Yao, G. Hu, Yao Xiao, Shuhua Yang, Wenhao Liu, Y. Qiao, Jianzong Shi, E. Du, Xiaofan Zhu, Shenning Wang","doi":"10.1175/jhm-d-22-0152.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0152.1","url":null,"abstract":"\u0000Climate changes significantly impact the hydrological cycle. Precipitation is one of the most important atmospheric inputs to the terrestrial hydrologic system, and its variability considerably influences environmental and socioeconomic development. Atmospheric warming intensifies the hydrological cycle, increasing both atmospheric water vapor concentration and global precipitation. The relationship between heavy precipitation and temperature has been extensively investigated in literature. However, the relationship in different percentile ranges has not been thoroughly analyzed. Moreover, a percentile-based regression provides a simple but effective framework for investigation into other factors (precipitation type) affecting this relationship. Herein, a comprehensive investigation is presented on the temperature dependence of daily precipitation in various percentile ranges over the Qinghai–Tibet Plateau. The results show that 1) most stations exhibit a peaklike scaling structure, while the northeast part and south margin of the plateau exhibit monotonic positive and negative scaling structures, respectively. The scaling structure is associated with the precipitation type, and 2) the positive and negative scaling rates exhibit similar spatial patterns, with stronger (weaker) sensitivity in the south (north) part of the plateau. The overall increase rate of daily precipitation with temperature is scaled by Clausius–Clapeyron relationship. 3) The higher percentile of daily precipitation shows a larger positive scaling rate than the lower percentile. 4) The peak-point temperature is closely related to the local temperature, and the regional peak-point temperature is roughly around 10°C.\u0000\u0000\u0000This study aims to better understand the relationship between precipitation and surface air temperature in various percentile ranges over the Qinghai–Tibet Plateau. This is important because percentile-based regression not only accurately describes the response of precipitation to warming temperature but also provides a simple but effective framework for investigating other factors (precipitation type) that may be affecting this relationship. Furthermore, the sensitivity and peak-point temperature are evaluated and compared among different regions and percentile ranges; this study also attempts to outline their influencing factors. To our knowledge, this study is the first integration of percentile-based analysis of the dependence of daily precipitation on surface air temperature.\u0000","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82637244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Saadi, C. Furusho‐Percot, Alexandre Belleflamme, S. Trömel, S. Kollet, R. Reinoso-Rondinel
{"title":"Comparison of three radar-based precipitation nowcasts for the extreme July 2021 flooding event in Germany","authors":"Mohamed Saadi, C. Furusho‐Percot, Alexandre Belleflamme, S. Trömel, S. Kollet, R. Reinoso-Rondinel","doi":"10.1175/jhm-d-22-0121.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0121.1","url":null,"abstract":"\u0000Quantitative precipitation nowcasts (QPN) can improve the accuracy of flood forecasts especially for lead times up to 12 hours, but their evaluation depends on a variety of factors, namely the choice of the hydrological model and the benchmark. We tested three precipitation nowcasting techniques based on radar observations for the disastrous mid-July 2021 event in seven German catchments (140-1670 km2). Two deterministic (advection-based and S-PROG) and one probabilistic (STEPS) QPN with maximum lead time of 3 h were used as input to two hydrological models: a physically-based, 3D-distributed model (ParFlowCLM) and a conceptual, lumped model (GR4H). We quantified the hydrological added value of QPN compared to hydrological persistence and zero-precipitation nowcasts as benchmarks. For the 14 July 2021 event, we obtained the following key results: (1) According to the quality of the forecasted hydrographs, exploiting QPN improved the lead times by up to 4 h (8 h) compared to adopting zero-precipitation nowcasts (hydrological persistence) as a benchmark. Using a skill-based approach, obtained improvements were up to 7-12 h depending on the benchmark. (2) The three QPN techniques obtained similar performances regardless of the applied hydrological model. (3) Using zero-precipitation nowcasts instead of hydrological persistence as benchmark reduced the added value of QPN. These results highlight the need for combining a skill-based approach with an analysis of the quality of forecasted hydrographs to rigorously estimate the added value of QPN.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83598568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Developing Impacts-Based Drought Thresholds for Ohio","authors":"Ning Zhang, Zhiying Li, S. Quiring","doi":"10.1175/jhm-d-22-0054.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0054.1","url":null,"abstract":"\u0000Drought monitoring is critical for managing agriculture and water resources and for triggering state emergency response plans and hazard mitigation activities. Fixed thresholds serve as guidelines for the United States Drought Monitor (USDM). However, fixed drought thresholds (i.e., using the same threshold in all seasons and climate regions) may not properly reflect local conditions and impacts. Therefore, this study develops impacts-based drought thresholds that are appropriate for drought monitoring in Ohio. We examined four drought indices that are currently used by the State of Ohio: Standardized Precipitation Index (SPI), Standardized Precipitation-Evapotranspiration Index (SPEI), Palmer’s Z-Index and Palmer Hydrological Drought Index (PHDI). Streamflow and corn yield are used as indicators of hydrological and agricultural drought impacts, respectively. Our results show that fixed thresholds tend to indicate milder drought conditions in Ohio, while the proposed impacts-based drought thresholds are more sensitive to exceptional drought (D4) conditions. The area percentage of D4 based on impacts-based drought thresholds is more strongly correlated with corn yield and streamflow. This study provides a methodology for developing local impacts-based drought thresholds that can be applied to other regions where long-term drought impact records exist to provide regionally representative depictions of conditions and improve drought monitoring.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89448182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hong Wang, F. Sun, Fa Liu, Tingting Wang, Yao Feng, Wenbin Liu
{"title":"The variability of pan evaporation over China during 1961-2020","authors":"Hong Wang, F. Sun, Fa Liu, Tingting Wang, Yao Feng, Wenbin Liu","doi":"10.1175/jhm-d-22-0232.1","DOIUrl":"https://doi.org/10.1175/jhm-d-22-0232.1","url":null,"abstract":"\u0000The most basic features of climatological normals and variability are useful for describing observed or likely future climate fluctuations. Pan evaporation (Epan) is an important indicator of climate change; however, current research on Epan has focused on its change in mean rather than its variability. The variability of monthly Epan from 1961 to 2020 at 969 stations in China was analyzed using a theoretical framework that can distinguish changes in Epan variance between space and time. The Epan variance was decomposed into spatial and temporal components, and the temporal component was further decomposed into inter-annual and intra-annual components. The results show that the variance in Epan was mainly controlled by the temporal component. The time variance was mainly controlled by intra-annual variance, decreasing continuously in the first 30 years, and slightly increasing after the 1990s. This is mainly due to the fact that the decrease of wind speed and the increase of water vapor pressure deficit with the temperature increase offset each other and inhibit the variability of Epan. The variance decreased more in the northern region, whereas it exhibited a small decrease or slight increase in the southern region. The reduction in seasonality was dominated by spring, followed by summer. The differences in Epan variability in space and season were mainly caused by the differing rates of change in evaporation driving forces, such as a greater reduction in wind speed in the northern region and spring.","PeriodicalId":15962,"journal":{"name":"Journal of Hydrometeorology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87474030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}