2022年夏季陕西关中持续高温干旱天气成因及对农作物的影响

2022年夏季陕西关中出现持续高温干旱天气，对玉米、苹果和猕猴桃等农作物生长发育造成严重影响。为研究此次高温干旱发生机制，利用关中地区46个自动气象站观测数据、欧洲中心ERA-5逐小时和月平均再分析资料等，研究主要高温时段大气环流特征和成因。结果表明：（1）主要高温时段为6月中下旬和8月上中旬，关中大部分地区出现中到重旱；（2）2个高温阶段均表现出下沉气流强盛的特征，但成因不同。6月高空异常的脊前负涡度平流输送在关中地区造成强烈的下沉运动，8月副高和南亚高压叠置，气候态正异常在陕西上空表现为异常强的下沉运动；（3）6月强盛的西北气流和8月副高异常偏西偏强使低层偏南气流减弱，阻断了水汽来源，均表现出水汽通量散度正异常，不利于出现有效降水；（4）高温干旱对粮食和经济作物产量和品质有一定影响，建议高温前采取有效措施，及时灌溉，降低田间温度，补充植株水分，增强植株蒸腾作用，降低农作物高温胁迫程度。

Analysis of Persistent High Temperature and Drought in Summer of 2022 and Its Impacts on Crops in Guanzhong of Shaanxi Province

Persistent high temperature and drought occurred in Guanzhong of Shaanxi Province in summer of 2022, causing serious impacts on the growth and development of crops such as maize, apple and kiwifruit. To study the mechanisms of the occurrence of heat and drought, observations from 46 automatic meteorological stations in Guanzhong area, and ERA-5 hourly and monthly mean reanalysis data were used to study the characteristics and causes of atmospheric circulation during the main high temperature periods. The results showed that (1) the main high temperature periods were mid-late June and early-mid August, with moderate to severe drought in most parts of Guanzhong. (2) Both high-temperature periods were characterised by strong sinking currents, but the causes were different. In June, strong sinking movements were maintained by anomalous pre-ridge negative vorticity advective, while in August, the superposition of the subtropical high and South Asian high caused the positive climate state anomalies and strong sinking movements over Shaanxi. (3) The strong northwesterly airflow in June and the abnormally westerly and strong subtropical high in August weakened the southerly airflow and blocked the source of water vapour, both showing positive anomalies of water vapour flux dispersion, which were not conducive to the occurrence of precipitation. (4) High temperatures and drought had an impact on the yield and quality of food and cash crops. It was recommended that effective measures should be taken before high temperatures to lower field temperatures, replenish plant water, enhance plant transpiration and reduce the degree of crop heat stress.