Abstract:

Artificial afforestation had rapidly reversed the ecology of the Hobq Desert. Understanding changes of the radiation components is of great significance for improving parameters of the land surface processes. We used a four-component radiometer to measure the radiation of the Caragana korshinskii shrub in the Hobq Desert from 2014 to 2016， and analyzed the characteristics of the radiation components under typical weather and different time scales in the area. Results showed that （1） under different weather conditions， radiation components had obvious diurnal variations， except for the downward long-wave radiation； On sunny days， the maximum values of the downward short-wave， downward long-wave， upward short-wave， and upward long-wave radiation were 940.8 ， 403.4， 53.6， and 865.8 W·m^-2， respectively. The daily averages of the radiation components were 203.7， 291.7， 7.7， 450.4 W·m^-2， respectively. （2） As for the diurnal variations， seasonal mean diurnal values of the downward short-wave radiation and upward long-wave radiation in different seasons peaked at 13 o'clock， while the upward short-wave radiation reached its peak at 14 o'clock. Diurnal variations of the downward long-wave radiation were small and the peak was not obvious. The seasonal averaged daily totals of the downward short-wave radiation were in the order of spring>summer>autumn>winter， and the daily totals of the other three components were summer>spring>autumn>winter. （3） As for the intra-year variations， the time when the four radiation components and the net radiation reached their peaks was not completely consistent. The downward short-wave radiation fluctuated the most， the other three components could reach the peaks in summer and the minimum in winter. （4） The income of the annual net radiation was greater than the expenditure. The net radiation changed from positive to negative at the beginning of November and then from negative to positive at the beginning of February of the following year. The monthly average net radiation during the study period was 37 W·m^-2， which suggested the area was a strong heat source.

Key words: Hobq Desert, artificial forest, different weather, radiation characteristics