黑龙江省粮食主产区雪水当量变化对土壤墒情的影响

Analysis of impact of changes in snowwater equivalenton soil moisture in main grain producing areas of Heilongjiang Province

土壤季节性冻融现象普遍存在于我国北方寒冷地区,是土壤水分时空分布剧烈变化的关键影响因素。雪水当量对积雪及冻土融化后土壤含水量有明显指示作用,对土壤墒情监测、预估和备春耕生产有指导作用。掌握季节性冻融过程中雪水当量、土壤水分状况和变化规律具有重要意义。利用全球环境变化观测卫星(GCOM-W1),分析并监测黑龙江省大豆、玉米、水稻产区的雪水当量和土壤含水量,空间分辨率为1 km。结果表明:2022年3月中下旬雪水当量高于历史平均,积雪积累丰富;4月初积雪迅速消融,雪水当量迅速减小,黑龙江省西北、东北和南部农区雪水当量在3月下旬和4月上旬高于历史同期,后逐渐与历史持平。2022年3—4月上旬,土壤含水量增高,变化趋势与雪水当量相反;3月下旬西部农区土壤含水率高于历史同期;4月上旬西部和东部大部分农区高于历史同期,4月中旬松嫩平原西部和三江平原中西部农区大风增温,失墒明显,部分农区土壤含水率低于2021年,但与近9a平均比仍持平或偏高。主要粮食产区雪水当量与土壤含水量呈显著负相关,即随着积雪融化,土壤含水量数值迅速增加;三种主要作物中,大豆产区随雪水当量减小,对土壤含水量影响最为显著。

The seasonal freeze-thaw phenomenon of soil is widespread in the cold regions of northern China.It is a critical period of intense spatial and temporal variations in soil moisture distribu-tion.The snow water equivalent plays a significant indicative role in the soil moisture content after snowmelt and frozen soil,and it provides guidance for soil moisture monitoring,estimation,and spring farming preparation.Therefore,understanding the snow water equivalent,soil moisture conditions,and their changing patterns during the seasonal freeze-thaw process is of great significance.Based on this,This research utilized the Global Change Observation Mission-Water(GCOM-W1)satellite to monitor and analyze the snow water equivalent and soil moisture content in the soybean,corn,and rice production areas of Heilongjiang Province.The spatial resolution was 1 km.The analysis indicated that in late March and early April 2022,the snow water equivalent was higher than the historical average,with abundant snow accumulation.By early April,the snow rapidly melted,leading to a rapid decrease in the snow water equivalent.The snow water equivalent in the northwest,northeast,and southern agricultural areas was higher than the historical average in late March and early April,gradually returning to historical levels thereafter.From late March to early April 2022,the soil moisture content increased,with a trend opposite to that of the snow water equivalent.In late March,the soil moisture content in the western agricultural areas was higher than the historical average,and in early April,most of the western and eastern agricultural areas were higher than the historical average.In mid-April,strong winds and warming in the western part of the Songnen Plain and the central-western part of the Sanjiang Plain led to noticeable soil moisture loss.In some agricultural areas,the soil moisture content was lower than the previous year,but still remained at or above the average of the past nine years.The snow water equivalent in the main grain-producing areas showed a significant negative correlation with soil moisture content,indicating that as the snow melted,the soil moisture content rapidly increased.Among the three main crops,the response of soil moisture content to the decrease in snow water equivalent was most significant in the soybean-producing areas.