Publications

Geng, GP; Yang, R; Liu, LZ (2022). Downscaled solar-induced chlorophyll fluorescence has great potential for monitoring the response of vegetation to drought in the Yellow River Basin, China: Insights from an extreme event. ECOLOGICAL INDICATORS, 138, 108801.

Abstract
Satellite solar-induced chlorophyll fluorescence (SIF) is a good probe for diagnosing the photosynthetic characteristics and stress response of vegetation dynamics to drought. However, most studies used the SIF products with coarse resolution from global to regional scales. In this study, based on a new global 'OCO-2' SIF data set (i. e., SIF obtained from the Orbiting Carbon Observatory-2, GOSIF) with a 0.05 spatial resolution from 2000 to 2018, using multi-scale standardized precipitation evapotranspiration index (SPEI), we analyzed the drought in the Yellow River Basin (YRB) and its correlation with vegetation dynamics, identified a typical drought event in 2004, and investigated the response process and discrepancies of different vegetation types to drought. The results showed that the YRB was overall in dry condition but showed a wetting trend during this period, mean SIF in the vegetation growing season presented a spatial pattern of high in the south and low in the north. The multi scale SPEI was mainly positively related to SIF in the YRB, and the areas of significant positive correlation between SPEI-3 and SIF were the largest, accounting for 37.06%, which were primarily located in the largest sub basin of the YRB, the Wei River Basin (WRB). Furthermore, an extreme drought from February to July 2004 in the WRB was selected as a typical drought event, and SIF showed varying standardized negative anomalies during this period. For different vegetation types, the promptest response to drought was observed in the case of the SIF of cropland followed by those of grassland and forest. SIF of cropland declined the most in July (18.44%), while SIF of forest and grassland declined the most in June and July (15.02% and 18.69%), respectively, indicating that the drought seriously affected vegetation growth and photosynthesis. In general, GOSIF has great potential for monitoring the response of vegetation to drought.

DOI:
10.1016/j.ecolind.2022.108801

ISSN:
1872-7034