2023年河西走廊中部异常高温干旱特征及其成因

Characteristics and causes of abnormal heat temperature and drought in the Central Hexi Corridor in 2023

  • 摘要: 2023年河西走廊中部出现了60a一遇的罕见复合高温干旱,对当地农业生产和生态环境产生不利影响,造成严重的经济损失。本文利用河西走廊中部6个国家基本站1951-2023年逐月降水和气温资料,黑河上游莺落峡水文站黑河径流量资料,FY-3D/MERSI卫星资料,GF-1卫星资料,NCEP/NCAR 月平均再分析资料,NCC提供的88项大气环流指数和26项海温指数,对2023年河西走廊中部高温干旱从气象、水文、生态、农业等多角度探讨了高温干旱特征及影响,重点分析了夏季降水对大气环流和关键区海温的异常响应。结果表明:河西走廊中部2023年5-9降水和平均气温均突破历史极值,创历史新高,高温的叠加效应,使干旱强度明显加重;引发祁连山中段积雪面积减少45.8%,黑河年径流偏枯15%,主要水库面积减少25.8%-66.0%。干旱的传递特征是气象干旱→水文干旱→生态和农业干旱。河西走廊中部5-9月降水存在5a、11a、17a、32a显著的多尺度振荡,多个时间尺度显示2023年处于偏少的振荡期。河西走廊中部干旱的异常环流特征包括以下特征,西太平洋副高脊线偏南、西伸脊点偏东、南亚高压脊点偏东、印度低压偏弱、北半球和亚洲区极涡面积偏小、亚洲中高纬度阻塞高压偏强、欧亚和亚洲地区西风环流经向度加大、Nino 3区和西风漂流区海温偏暖、黑潮区海温偏冷。

     

    Abstract: The 2023 compound heat and drought event occurred once in 60 years in central Hexi Corridor, which adversely affected local agricultural production and the ecological environment and caused serious economic losses. This study uses various observational datasets to discuss the characteristics and effects of the high-temperature drought in the central Hexi Corridor in 2023 from the perspectives of meteorology, hydrology, ecology and agriculture. We further examine responses of summer precipitation in the central the Hexi Corridor to anomalous atmospheric circulation and sea surface temperature (SST). These datastes include monthly precipitation and temperature data during 1951-2023 from six national basic stations in the central Hexi Corridor, Heihe River runoff data from Yingluoxia hydrological Station in the upper reaches of Heihe River, FY-3D/MERSI satellite data, GF-1 satellite data, and NCEP/NCAR monthly mean reanalysis data, the 88 atmospheric circulation indexes and 26 SST indexes provided by NCC. The results show that the mean precipitation and average temperature in the central Hexi Corridor from May to September, 2023, monthly average temperature in June, August and September broke through the historical extreme values and reached record highs. In the middle Qilian Mountains, the averaged snow cover area decreased by 45.8%, the annual runoff decreased by 15%, the main reservoir area decreased by 25.8%-66.0%. The transmission characteristics of drought are meteorological drought → hydrological drought → ecological and agricultural drought. We find that precipitation in the central of Hexi Corridor from May to September has significant multi-scale oscillations in 5a, 11a, 17a and 32a, and multiple time scales show that 2023 is in a period of less oscillation. When the drought in the central the Hexi Corridor is observed, the atmospheric circulation anomalies include: a southward shifted ridge line of the subtropical high in the Western Pacific Ocean, the eastward shifted ridge point of the western extension, the westward shifted ridge point of the South Asian high pressure, a weak Indian low is weak, the small polar vortex area in the northern hemisphere and Asia, the strong blocking high in the middle and high latitudes in Asia is strong, the increased longitude of the westerly circulation in Eurasia and Asia. Meanwhile, The SST anomalies are warm in the Nino3 area and the west wind drift region, but cold in the Kuroshio region.

     

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