河北省土壤表面冻融物候特征及其对气候变化的响应

Characteristics of soil surface freezing and thawing in Hebei Province in response to climate change

基于1981—2006年河北省土壤表面冻融物候观测资料和气象资料,研究了河北省土壤表面冻融物候的空间和时间变化特征及对气候变化的响应。结果表明:河北省地表始冻期、解冻期和封冻期随纬度、高度不同存在很大差别,东南平原地区地表始冻期偏晚,解冻期偏早,封冻期较短,而北部、西北部地区地表始冻期偏早,解冻期偏晚,封冻期较长;相比物候期多年均值,20世纪90年代初之前,河北省地表始冻期以提前年份为主,解冻期以推迟年份为主,封冻期以延长年份为主;20世纪90年代后期之后河北省绝大部分地区地表解冻期显著提前,始冻期推迟,封冻期缩短;地势较低地区的地表冻融物候与气温显著相关,河北省秋季气温上升1℃,地表始冻期推迟3.8d,2—3月气温上升1℃,地表解冻期提前5.3d,响应幅度大于始冻期对秋季气温的响应幅度;10月—翌年3月气温上升1℃,河北省地表封冻期缩短12.6d。

Based on the 1981-2006 phenological and meteorological data of Hebei Province, the spatiotemporal characteristics of soil surface freezing and thawing in the province in response to climate change were analyzed. An obvious regional difference was observed in the phenological phases of soil surface freezing and thawing. In the southeast coastal plain area of the province, the beginning phase of freezing was later, thawing phase was earlier, and frozen phase was shorter; while in the north and northwest mountain areas, they were in contrary. Compared with the past years average phenological dates, the beginning phase of freezing in the province before the early 1990s was earlier, thawing phase was later, and frozen phase was longer, but after the late 1990s, the beginning phase of freezing in most areas of Hebei Province delayed, beginning phase of thawing advanced, and frozen phase shortened. Air temperature had significant effects on the phenological phases of soil surface freezing and thawing in the areas with lower terrain. In case that the air temperature in autumn was increased by 1 ℃, the beginning phase of freezing would be delayed 3.8 days. If the temperature from February to March increased 1 ℃, the beginning phase of thawing would be 5.3 days earlier; if the air temperature from October to next March increased 1 ℃, the frozen phase would be shortened by 12.6 days.