Diurnal temperature range variation and its causes in a semiarid region from 1957 to 2006

Abstract The formation of artificial lake due construction of a hydroelectric plant causes irreversible environmental impacts. Studies associated with these artificial lakes for the Brazilian semiarid region are still insufficient. Thus, the objective of this study is to provide new information on the trends of climatic extremes, dependent on rainfall and air temperature, for the Sobradinho Hydroelectric Power Plant (SHPP) lake region, through the analysis of climate change indices. This study is particularly important for the SHPP region because microclimate changes have significant impacts on the natural, social and economic sectors. For the two analyzed stations (Bebedouro-PE and Mandacaru-BA), it is not possible to affirm that the construction of the SHPP artificial lake altered the local microclimate. Trends of increase in maximum temperature, the number of hot days and diurnal temperature range were noticed. However, the rise of these indices cannot be attributed to the formation of the SHPP lake. The influence of the SST of Tropical Oceans on the temporal behavior of some of the indices used in this study may have contributed to increases in hot days and nights, maximum temperature, diurnal temperature range and consecutive dry days over the region.

Download Full-text

The Spatiotemporal Patterns of Climate Asymmetric Warming and Vegetation Activities in an Arid and Semiarid Region

Climate ◽

10.3390/cli8120145 ◽

2020 ◽

Vol 8 (12) ◽

pp. 145

Author(s):

Tong Heng ◽

Gary Feng ◽

Ouyang Ying ◽

Xinlin He

Keyword(s):

Diurnal Temperature Range ◽

Vegetation Index ◽

Extreme Values ◽

Terrestrial Ecosystems ◽

Spatiotemporal Patterns ◽

Semiarid Region ◽

Diurnal Temperature ◽

Temperature Range ◽

Warming Rate ◽

Nighttime Warming

Asymmetric warming was bound to have a major impact on terrestrial ecosystems in arid regions during global warming. Further study was necessary to reveal the spatiotemporal patterns of asymmetric warming in Xinjiang; this study analyzed the climate and normalized difference vegetation index (NDVI) data (2000–2020). The change trends of the day and nighttime warming (DNW), seasonal warming, and the diurnal temperature range in northern Xinjiang (S1) and southern Xinjiang (S2) were determined. The findings indicated that the DNW rate showed a significant (p < 0.05) upward trend, especially in winter. The nighttime warming rate (0.65 °C (decade)−1) was faster than the daytime warming rate (0.4 °C (decade)−1), and the diurnal temperature range between daytime and nighttime exhibited a decreasing trend. The diurnal temperature range was the highest in spring and the lowest in winter. Extreme values of the diurnal temperature range appeared in autumn (48.6 °C) and winter (12.3 °C) and both in S1. The Tmin in S1 had an abruption trend in 2006–2017, the Tmax in S2 had an abruption trend in 2005–2011, and the probability of spatial abruption in S1 was higher than that in S2. The partial correlation between the NDVI and Tmin was significantly higher than that between the NDVI and Tmax in the area where the significance test passed; therefore, asymmetric nighttime warming had a greater impact on the NDVI than the asymmetric daytime warming.

Download Full-text