The 2010 spring drought reduced primary productivity in southwestern China

Abstract

Many parts of the world experience frequent and severe droughts. Summer drought can significantly reduce primary productivity and carbon sequestration capacity. The impacts of spring droughts, however, have received much less attention. A severe and sustained spring drought occurred in southwestern China in 2010. Here we examine the influence of this spring drought on the primary productivity of terrestrial ecosystems using data on climate, vegetation greenness and productivity. We first assess the spatial extent, duration and severity of the drought using precipitation data and the Palmer drought severity index. We then examine the impacts of the drought on terrestrial ecosystems using satellite data for the period 2000-2010.Our results show that the spring drought substantially reduced the enhanced vegetation index (EVI) and gross primary productivity (GPP) during spring 2010 (March-May). Both EVI and GPP also substantially declined in the summer and did not fully recover from the drought stress until August. The drought reduced regional annual GPP and net primary productivity (NPP) in 2010 by 65 and 46 Tg C yr −1 , respectively. Both annual GPP and NPP in 2010 were the lowest over the period 2000-2010. The negative effects of the drought on annual primary productivity were partly offset by the remarkably high productivity in August and September caused by the exceptionally wet conditions in late summer and early fall and the farming practices adopted to mitigate drought effects. Our results show that, like summer droughts, spring droughts can also have significant impacts on vegetation productivity and terrestrial carbon cycling.

Responses of Natural Vegetation to Different Stages of Extreme Drought during 2009–2010 in Southwestern China

“…The rainfall percentage anomaly in some regions was 60.4% less than in previous years [5] and rainfall in February decreased by 49.5% compared to 2000-2009 average precipitation [38]. The continuous drought in the autumn, winter, and spring in some regions of Yunnan and Guizhou provinces was the most serious since 1880, and the extent and severity of drought broke historical records [5].…”

“…From 2009 to 2010, Southwestern China experienced a serious drought that affected extensive regions from Yunnan, Guangxi to Sichuan, Guizhou and Chongqing [5,38]. Figure 1 shows the unchanged land cover of Southwestern China, and the red square defines the study area.…”

Variation of Aridity Index and the Role of Climate Variables in the Southwest China

“…The abrupt decrease in precipitation favored the intensification, such as severity, duration and extent, of the severe drought event for this area. Fortunately, the precipitation was larger for 2014 and 2015 (Figure 4a), which could mitigate the drought severity of 2009-2011 [12,[51][52][53].…”

Monitoring the impact of aerosol contamination on the drought-induced decline of gross primary productivity

“…Because the affected area is a major grain-producing region that includes a large population and complex land cover, this severe drought event not only significantly affected the daily lives of millions of people but also impacted the structure, function, and services of terrestrial ecosystems (Qiu, 2010). Zhang et al (2012) recently reported on a severe decline in ecosystem productivity in southwestern China in the springtime of 2010. Nearly 63% of the region exhibited a decline in vegetation productivity (e.g., a reduction of 4% and 5% in regional annual GPP and NPP in 2010, respectively).…”

“…To reconcile these inconsistencies, this study examined the quality of data used in the recent study by Zhang et al (2012). The main objectives of this study aimed to address the following questions: (1) Was the MODIS GPP product affected by atmospheric contamination during the 2010 springtime drought period?…”