黑龙江省春季浅层(0～20cm)地温变化特征及预报

利用1981-2012年黑龙江省74个气象观测站的气温、0 cm、10 cm、20 cm地温春季(3-5月)逐日资料,分析了黑龙江省春季浅层地温、气温变化特征.结果表明:0 cm地温年际间波动大,全省平均1987年最低,2008年最高;全省变化存在明显的空间一致性;尽管气候变暖使1990年代以后春季0 cm地温偏低年出现相对减少,但是出现春季浅层地温偏低的年份比例仍超过三分之一,并具有南部、北部反向变化的特征,2005年以后南北差异有减小的趋势.各地3月份开始解冻,主要农区10 cm地温稳定通过6℃的日期主要集中在4月中下旬.以10 cm地温为预报量,利用黑龙江省逐日气温、20 cm地温资料建立春季浅层地温预报模型,回代和2013年预报检验平均绝对误差平均为1.05℃,绝对误差最大值为1.9℃,4月份的预报结果要好于3、5月,可以应用于业务指导.

Variation features and prediction of the topsoil (0~20-cm) ground temperature of spring in Heilongjiang Province

Based on the data of daily mean air temperature and topsoil ground temperature (0-cm, 10-cm and 20-cm) in spring (March to May) from 74 weather stations in Heilongjiang Province from 1981 to 2012,the temporal-spatial characteristics of the topsoil ground temperature in spring are analyzed. According to the spatial distribution of EOF2, the south area and the north area are defined in the province. The main conclusions are as follows: The topsoil ground temperature of spring in the province has obvious annual fluctuation. More specifically, the temperature plunged to the lowest point in 1987 and to the peak in 2008.
Despite the fluctuation, the topsoil ground temperature from 1981 to 2012 had increased. However, there were nine years with the topsoil ground temperature lower than the normal since 1991. There is a significant positive correlation between the ground temperatures at 10-cm depth and at 0-cm or 20-cm depth. The topsoil begins to thaw in March and the ground temperature at 10-cm depth stands at 6 ℃ mainly in April by adopting a 5-day running mean method. Taking the air temperature and the 20-cm ground temperature as two factors, the 10-cm ground temperatures are predicted by using the dual linear regressive model from 1981 to 2012 for every weather observations in Heilongjiang Province. The absolute error averaged over the province is 1.05 ℃ and the error in April is the minimum among three months of spring. The average absolute error is 1.05 ℃ and the maximum error is 1.9 ℃ for a prediction of 10-cm ground temperature of spring, 2013.