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

Abstract

International audienceThe diurnal temperature range (DTR) is an important indicator of climate change, and it has decreased worldwide since the 1950s, particularly over arid and semiarid regions. This study analyses the effect of meteorological and anthropogenic factors on DTR variation to investigate the possible causes of DTR decreases in semiarid climates. The study region is located in northeast China, and the study period is from 1957 to 2006. There are three main results. First, the rate of decrease in the DTR is −1.24 K per 50 years. This decrease is mainly attributed to the increasing daily minimum temperature rate (Tmin, 2.24 K per 50 years), which is greater than the change in the daily maximum temperature (Tmax, 1.00 K per 50 years). Second, sunshine duration (SD) appears to be the most significant meteorological factor that determines the DTR through downward shortwave radiation (Rsw,d) and surface soil moisture (SM). The effect of Rsw,d is larger for Tmax than for Tmin; therefore, the decrease in Rsw,d results in a smaller increase in Tmax than in Tmin. On the other hand, the increase in SM can strengthen daytime latent heat release, and the increase in Tmax is then slowed because of the cooling effect of evaporation. The precipitation values and the leaf area index show a negative correlation with the DTR, whereas the cloud amount and the relative humidity appear not to be main causes of the DTR decrease in this region. Finally, atmospheric aerosols can reduce the SD by 0.27 h year–1 by decreasing atmospheric transparency, as indicated by an analysis of the Total Ozone Mapping Spectrometer Aerosol Index from 1979 to 2005. The decrease in direct solar radiation is the main cause of decreases in Rsw,d. These findings will provide references for DTR variation studies in similar climates

Temperature and precipitation changes over the Loess Plateau between 1961 and 2011, based on high-density gauge observations

“…Rates of change for TM and TN showed similar spatial patterns, with the warming in the southeast region being generally weaker than the warming in the northwest region; however, for TX, severe warming was observed in the southeast. The increase in TN was larger than the increase in TX across the plateau as a whole, which is consistent both with global trends (Braganza, 2004;Lewis and Karoly, 2013) and with other regional trends (Shen et al, 2014;Wang et al, 2014). The inconsistent rates of change between TX and TN result in a general decrease in DTR, which is highly sensitive to small changes in either TX or TN (Dai et al, 1999).…”

The intensification of thermal extremes in west Africa

“…As reported over most locations over land (Easterling et al, 1997;Braganza et al, 2004;Wang et al, 2014), nocturnal/Tn warming is greater than diurnal/Tx warming since the mid-20 th century, which results in a decrease in diurnal temperature range (DTR). However, the opposite tends occurred over the post-1980s period.…”

Spatiotemporal change of diurnal temperature range and its relationship with sunshine duration and precipitation in China

“…The DTR was also strongly correlated with SD in all the seasons during the study period (Table ). This is consistent to the work conducted in Northeast China [ Wang et al ., ], Northeast India [ Jhajharia and Singh , ], and lower elevation sites in the Swiss Alps [ Rebetez and Beniston , ]. The similarities in temporal patterns of national DTR and SD (Figures and ) suggest that the declines in SD could be one of the causes for the decline of DTR.…”

“…DTR variation has regional and seasonal characteristics due to complicated interactions of local climatic and anthropogenic factors [ Karl et al ., , ; Easterling et al ., ]. Many scholars have studied the variation of DTR in China, showing that DTR decreased significantly in China over the past several decades [e.g., Karl et al ., , ; Kukla and Karl , ; Dai et al ., , ; Liu et al ., ; Ye et al ., ; Zhou and Ren , ; Wang and Dickinson , ; Xia , ; Wang et al ., ], but most of them focused on DTR changes at the national scale. Chen and Chen [] analyzed the spatial variation of DTR in China, but they mainly studied the declining trends of DTR during the whole study period.…”