The current monitoring season (July to October) covers the harvest of all spring crops in North-east China. Maize, rice and soybeans reached maturity in August and September in Heilongjiang, Jilin and Liaoning Provinces, and the harvest will be over by the end of October.
Precipitation was 35% higher than average, temperature was 0.1℃ lower, and the photosynthetic active radiation was 1% down. Temperatures from July to October were basically average throughout the monitoring period, except for a cold and very wet spell in August brought by Typhoon Lekima (section 5.2 for details). Altogether, agro-climatic conditions resulted in 5% below average potential biomass, reaching 10% in the North-east and West of Heilongjiang. Although Heilongjiang province was affected by several typhoons, they also brought excessive precipitation which are beneficial for crop development and grain-filling.
According to the spatial clusters of NDVI departure from average, the major rice producing areas in the north-eastern Heilongjiang and western Jilin Provinces had above average crop condition. However, in the southern and western Liaoning Province, NDVI was below average before August and recovered to average in early September. The VCIx map shows that higher VCIx values were mostly located in the western and northern parts of the region, with values above 1.0. This is an indication of favorable crop condition at peak growing season. VCIx exceeds 0.8 over almost the whole region. In general, crops did well in North-east China with overall good prospects for crop yield.
本监测期（7月-10月）覆盖中国东北地区所有春播作物的收获季节。黑龙江、吉林、辽宁三个省份包括玉米、水稻和大豆等作物于 8-9 月份成熟，秋收工作于10月底基本完成。东北地区降水较平均水平明显偏高35%，平均温度偏低0.1℃，光合有效辐射降低1%。从时间上来看，整个监测期内各旬气温多处于平均水平，仅8月初受台风“利奇马”影响出现低温多雨天气(灾害影响状况详见5.2节)。光温水三要素综合作用导致潜在生物量低于平均水平5%，黑龙江东北部和西部地区偏低幅度达到10%。2019年黑龙江省虽多次受到台风影响，但台风带来的充沛的降水为作物生长和产量形成提供了充足的水分保障。依据NDVI距平聚类图，黑龙江省东北部和吉林省西部主要水稻产区的作物状况均高于平均水平。然而，辽宁省南部和西部地区8月份之前的作物长势始终低于平均水平，8月初的充足降水使得该地区作物在9月初恢复至平均水平。最佳植被状况指数空间分布图则显示VCIx值较高的地区主要集中在西部和北部地区，部分地区VCIx值超过1.0，表明该地区作物生长高峰期长势超过近5年最佳状况，全区几乎所有地区的VCIx值均超过0.80。总体而言，2019年中国东北地区作物长势较好，作物丰产。
图4.7 2019年7月-10月东北区作物长势
（a） 基于NDVI的作物生长过程线
（b） NDVI距平聚类图（与5年平均相比）
（c）时间序列（旬）温度过程线
（d） 最佳植被状况指数
(e) 时间序列（旬）降水过程线
（f）潜在生物量距平（与5年平均相比）