Contrasting drought impacts on the start of phenological growing season in Northern China during 1982–2015

Abstract

Drought is a widely occurring extreme climatic event that may have various effects on vegetation phenology and activity. The change of the start of the phenological growing season (SOS) is one key mechanism for ecosystem responses to droughts yet remain unknown at large scale. This study used abnormal changes in the ratio of reference evapotranspiration (ETO) and precipitation (P) to detect the pre‐season (defined as the 3 months before the growing season) monthly drought during 1982–2015. After that, the pre‐season drought impacts on SOS were analysed. Drought appeared frequently (>3.6 times/10 years) in the northern and southwest China, as well as the coastal area of south China during the last 34 years. The droughts generally accompany a higher temperature and a stronger radiation, but the drought effects on the SOS differ between humid/sub‐humid and semi‐arid zones in northern China. Specifically, in the temperate humid/sub‐humid zones, SOS under drought was 1.08–4.86 days earlier than during normal (no drought) years, and the response was greater to the droughts that appeared in the first two of the three pre‐season months. In addition, in the cold, mid‐, and warm temperate zones, the advance response was more concentrated in the SOS about DOY130‐140, DOY125‐150, and DOY80‐160, respectively. However, in the north semi‐arid zone, the SOS under drought was 0.66–3.45 days later than during normal years, and the response was greater to the droughts that appeared in the last two of the 3 months. These delay responses also concentrated in the SOS about DOY125‐150. The contrasting drought impacts on phenology suggest that we should move beyond the vegetation activity under droughts such as the growth, productivity, and mortality, and pay more attention to the timing of vegetation activity to better quantify the carbon budget at Northern Hemisphere.

Concurrent Precipitation Extremes Modulate the Response of Rice Transplanting Date to Preseason Temperature Extremes in China

“…We hypothesized that rice in drier regions was more vulnerable than in wetter regions during extremely hot conditions. Because high temperatures contributed to greater vapor pressure deficits and increased water demand in drier areas than in wetter areas, transplantation was further prevented since the early growth stage was susceptible to water deficiency (H. Deng et al., 2020; Yuan et al., 2020).…”

The Dynamic of Vegetation Growth with Regular Climate and Climatic Fluctuations in a Subtropical Mountainous Island, Taiwan

“…Previous evaluations show that longer extension of LOS significantly relates to advanced SOS [33][34][35]. However, several studies have exhibited the contrast results that the SOS shows a slower advanced rate or delayed after 2000 due to drought and deficiency of soil moisture [36,37], and climate extremes [38]. Further analysis is necessary to ascertain this trend at a regional scale because the interannual variability of LSP is changing with the warming climate.…”

Spatio-Temporal Development of Vegetation Carbon Sinks and Sources in the Arid Region of Northwest China

“…Recent desert-oasis transition zones in the basin of NWC showed a reduction in area in response to the warming climate and human activities [ 35 ]. Deng et al [ 36 ] found that the start time for the phenology growing season was 0.66–3.45 d later than that of previous years under drought condition. In addition to damaging ecosystems, the variations in vegetation carbon sinks and sources can exert growing pressures on economic development and social stability.…”