The out‐of‐phase pattern of summer precipitation over northern China and the possible mechanisms

International Journal of Climatology, Journal Year: 2024, Volume and Issue: 44(12), P. 4428 - 4442

Published: Aug. 7, 2024

Abstract This study explored the interannual characteristics of out‐of‐phase pattern summer precipitation over northern China during past years, as well possible underlying mechanisms. The is characterized by positive anomaly in Northwest (NWC) and negative North (NC). Our analyses indicate that variation Asian westerly jet (AWJ) found evidently associated with this precipitation. meridional displacement AWJ induces opposite trends water vapour transport circulation anomalies between NWC NC, leading to pattern. Further suggest Arctic sea ice concentration (SIC), Atlantic Pacific surface temperature (SST) can impact triggering Eurasian (EU), polar‐Eurasia (POL) Pacific‐Japan (PJ) teleconnection patterns, respectively, which turn modulate formation primarily affected SST anomalies, whereas NC notably influenced both SIC anomaly. However, role on exhibits an evident contrast,

Language: Английский

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Remote Sensing Data Assimilation to Improve the Seasonal Snow Cover Simulations Over the Heihe River Basin, Northwest China

International Journal of Climatology, Journal Year: 2024, Volume and Issue: 44(15), P. 5621 - 5640

Published: Nov. 6, 2024

ABSTRACT The reliability of seasonal snow cover information is constrained by limitation in situ observations and uncertainties remote sensing data model simulations alpine region, thus posing important challenges to understanding the climate system water resource management region. Here, assimilation daily cloud‐free Moderate Resolution Imaging Spectroradiometer (MODIS) normalised difference index (NDSI) product into an intermediate complexity mass energy balance model—Flexible Snow Model (version FSM2_MO)—was implemented. aim improve (snow‐covered extent; SCE, depth; SD, equivalent; SWE, snowmelt runoff; SMR) region (a case upper‐middle reaches Heihe River basin, Northwest China). results indicate comprehensive improvement simulation SMR study area through assimilation, with ability significantly reduce prior biases FSM2_MO. Based on independent Advanced Very High Radiometer (AVHRR) SCE product, updated (i.e., assimilation) showed a reduction mean absolute error (MAE) from 10.46% 7.16%, root square (RMSE) 16.14% 12.26%, increase Pearson's correlation coefficient (CC) 0.18 0.67 compared open loop without assimilation). evaluation SD observation that improved run (OL). And utilising monthly discharge at Yingluoxia hydrological station, slightly simulation. achieved CC 0.91, Nash‐Sutcliffe efficiency (NSE) 0.73, Kling‐Gupta (KGE) 0.76. Moreover, Landsat 8‐derived map Sentinel‐1‐derived also indicated effectively filled missing removed superfluous predicted OL terms spatial distribution.

Language: Английский

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Dynamic Evolution and Copula-Based Multivariable Frequency Analysis of Meteorological Drought Considering the Spatiotemporal Variability in Northwestern China

Water, Journal Year: 2023, Volume and Issue: 15(21), P. 3861 - 3861

Published: Nov. 6, 2023

Meteorological drought is a continuous spatiotemporal phenomenon that poses serious threat to water resource security. Dynamic evolution and multivariable frequency analysis of meteorological are important for effective mitigation risk management. Therefore, this study aims analyze events in northwestern China between 1960 2018 based on the standardized precipitation evapotranspiration index (SPEI) through three-dimensional identification method. This investigates dynamic different time space scales evaluates considering variability Copula. The results show SPEI presents an upward trend Northwestern China. A towards increased humidity observed arid regions, contrasted by aridification semi-arid semi-humid areas, indicating spatial distribution area tends homogenization. possibility high-intensity occurring same was relatively low, whereas low-intensity were frequent. Additionally, analyzes migration process individual from perspective. Neglecting any one variable could significantly underestimate probability severe events. plays crucial role formulation prevention strategies, as well forecasting.

Language: Английский

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Changes in Persistent Precipitation in Northwest China and Related Large-Scale Circulation Features

Journal of Meteorological Research, Journal Year: 2023, Volume and Issue: 37(5), P. 604 - 616

Published: Oct. 1, 2023

Language: Английский

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Asymmetric Drying and Wetting Trends in Eastern and Western China

Advances in Atmospheric Sciences, Journal Year: 2023, Volume and Issue: 41(2), P. 221 - 232

Published: March 9, 2023

Language: Английский

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