曲周地区早、中全新世古年径流深状况的推估

利用中国北方 30个小汇水流域的现代资料数据建立了年平均温度和年降水-年平均径流深关系式 ;利用先前测得的河北平原南部曲周地区的河间洼地沉积物的磁化率和碳酸盐氧同位素组分以及其他研究者建立的磁化率与气候变量之间的关系式和氧同位素组分与气候变量之间的关系式 ,推估了曲周地区早、中全新世的古年温度状况和古年降水状况 ;以推估的古年温度和古年降水以及建立的年平均温度和年降水-年平均径流深关系式 ,推估了曲周地区早、中全新世的古年径流深状况。

Inferences of the past annual runoff of the early and middle Holocene for Quzhou area, the southern Hebei Plain

A relationship between mean annual temperature, mean annual precipitation and mean annual runoff was derived with the contemporary data for 30 small catchments in northern China. With the relationship between magnetic susceptibility and climatological variables and between oxygen isotopic compositions and climatological variables established by other investigators, the past annual-temperature and annual-precipitation of the early and middle Holocene were inferred for Quzhou area situated in the southern Hebei Plain from the previously measured magnetic susceptibility and carbonate oxygen isotopic composition of sediments sampled in an inter-channel depression in this area. With the derived relationship between mean annual temperature, mean annual precipitation and mean annual runoff, the corresponding past annual-runoff of the early and middle Holocene was inferred for this area from the so inferred annual-temperature and annual-precipitation. During >10,210-10,000 yr BP, the annual runoff was abundant and apparently more than nowadays. It was relatively spare, being probably less than, roughly the same to or still more than during the contemporary time in 10,000-8,500 yr BP. In 8,500-8,000 yr BP, the annual runoff was again remarkably more than that in the modern time. It was relatively rare again during 8,000-7,200 yr BP. From 7,200 yr BP onwards, the annual runoff tended to increase and was extremely abundant at ～6,700 or 6,500 yr BP when it might be 2.4, 3.4, 4.1 or even 5.0 times more than today. After ～6,000 yr BP, it began to gradually decrease. The general trend of variations in annual runoff inferred for Quzhou area is generally similar to those inferred by other investigators for other parts of the Hebei Plain. However, the comparison of our estimates with those of other investigators indicates that the surface water was much more abundant in Quzhou area than in other parts of the Hebei Plain during the mid-Holocene (7500-5500 yr BP).