Analysis On Spatiotemporal Variation Characteristics Of Agricultural Threshold Temperature And Land Surface Temperature In Heilongjiang Province During Recent 50 Years

In this paper based on the daily air temperature data and daily land surface temperature data in the 78 meteorological stations in Heilongjiang province from 1965-2014, by screening and missing measurement interpolation using many analytic methods, such as 5-day sliding average method、climate tendency rate regression analysis method、anomaly analysis method、correlation analysis method though SPSS、inverse distance weighted interpolation method, the temporal and spatial changes of beginning and ending date、duration of 0℃、3℃、5℃、10℃threshold temperature and land surface temperature are analyzed, make the Schedule of spatial and temporal variation characteristics of agricultural threshold and land surface temperature in Heilongjiang province to get a more intuitive understanding of the agricultural threshold temperature and land surface temperature change trends, in order to provide data reference for agricultural sowing and selection of crop sui Tab. area. The statistical results show that:(1) On temporal scales, the beginning date of the threshold temperature in recent 50 years from 1965-2014 in Heilongjiang province shows a trend in advance for generally 4-6 days, the beginning date of ≥10℃ threshold temperature is most significant in advance and the the beginning date of ≥3℃threshold temperature is the slowest in advance; Ending date of the threshold temperature shows a trend of delay for 4-7.5 days, the ending date of ≥0℃threshold temperature is most significant of delay and the ending date of the threshold temperature is the slowest of delay; The beginning date of ≥0℃ threshold temperature in Mudanjiang region appears the earliest and the ending date in Daqing region appears the latest, while the beginning date of the other threshold temperature in Daqing region appears the earliest, Daxing’an Mountain range in northwest appears the latest and the ending date in Daqing region appears the latest, Daxing’an Mountain in northwest range appears the earliest. The rate in advance of threshold temperature is greater than the rate of delay.The duration of threshold temperature shows a trend of increase for 9-14 days, ≥0℃threshold temperature which represents sui Tab. farming period increases the most significant. Different among the threshold temperature of ≥0℃、≥3℃、≥5℃is small because the differences among the beginning and ending date of threshold temperature is small as well. The threshold temperature duration of the southern region(such as Daqing and so on) lasts longer and Daxing’an Mountain range in northwest lasts the shortest.(2)On spatial scales, the beginning date of threshold temperature shows a trend in advance 、the ending date shows a trend of delay and the duration shows a trend of in crease with the latitude decreases; The north-south differences of threshold temperature beginning date is large and the north-south differences of threshold temperature ending date is small with the latitude changes. Threshold temperature duration U-shaped increases from north to south, duration of most of the south region lasts long except for ≥10℃threshold temperature because the influence of monsoon in spring and autumn and high-pressure leds to the high numerical region in southeast is not significant. The low temperature area in the north region decreases year by year.(3)On temporal areas, land surface temperature and seasonal land surface temperature shows a rising trend in Heilongjiang province from 1965-2014, mutation appears in 1990 s which lead to the land surface temperature increased significantly. The rate that the land surface temperature increased 0.874℃/10 a and the average temperature is 5.01℃. During the recent 50 years studied, land surface lowest temperature is 2.91℃in1972a while highest temperature is 8.54℃in 2014a; Average land surface temperature is the lowest in Daxing’an Mountain range and highest in Qitaihe region, it increased most significantly in Heihe region.The lowest seasonal land surface temperature appears in Daxing’an Mountain range, the highest land surface temperature in spring and summer appears in Daqing region, the highest land surface temperature in autumn appears in Jixi region the highest land surface temperature in winter appears in Qitaihe region because of the influence of monsoon and air pressure. It comes to the conclusion according to the research of the decadal study the the land surface temperature falls at a speed of 1.52℃/10 a in the first generation from 1965-1974 a, then the rate of decline levels off and begins to increase significantly in the mid-1980 s.(4)On temporal areas, average land surface temperature U-shaped trend increase significant with the latitude decreases, land surface temperature increase 1.1℃ with latitude decrease 1°while the low temperature appears in the northwest region and high temperature appears in the southwest and southwest region; Low temperature areas reduce and high temperature areas expand with the generational change.Four seasons land surface temperature low-temperature appear in the southwest area, high land surface temperature mainly appears in the southwest area in spring, the northeast northeast high-temperature area disappears gradually in summer because of the monsoon from Sanjiang Plain, the southeast high-temperature area appears again after crossing the monsoon in autumn and winter. Land surface temperature is significant affected by the heat resources such as air temperature.