The Stable Isotope Temporal-spatial Distribution Of Modern Precipitation Over East Monsoon China And Its Implication For Climate

Stable isotopes of precipitation contain a variety of climate information, and its ratios are associated with vapor source, other meteorological factors in the final rainy areas. So it can actually reflect the weather and climate characteristics. The isotopes of temporal-spatial distribution in precipitation and environmental effects can be used in inversing the atmospheric processes, tracing the water circulation and supporting assistance forδ18O of geology research in reconstructing paleoclimate.In this paper, by using the stations data of Global Network of Isotope in Precipitation and the observed meteorological data, we put forward the meteoric water line (δD=7.557δ18O+6.808) of the monsoon area in our country, comparison with the worldwild one reveals most vapor source of this area is marine air mass, and the difference between the southern line (δ<D=7.683δ18O+8.347) and northern line (δD=7.144δ18O+1.367) shows south area is moister than north. The statistics on the year-round deuterium surplus also proves the change property of precipitation is consistent with the characteristic that tropical marine air mass and polar continental air mass is the main during summer and winter monsoon time. Analyzing isotopes of temporal-spatial distribution and environmental effects, we find the correlation coefficients of "temperature effect" and "amount effect" change from negative to positive along the low latitude to the high and the zero coefficient areas locate nearby the boundary of south and north, the territory affected and unaffected by monsoon. The year-round isotopic compositions also indicate the change of monsoon and rain band over the east, it suggests the monsoon and different vapor source may control the δ18O ratios. By the high correlation of δ18O between Zhengzhou and Xi’an, the comparison of long term inter-annual variations of stable isotope is summer precipitation with vapor transportation intensity and monsoon index, we think annual and inter-annualδ18O ratios also shows the convert of monsoon circulation over Asia. There are confusions with reasonable explanation of the δ18O significance of speleothems in reconstructing paleoclimate. In our research, we think theδ18O ratios of speleothems is controlled by Asian monsoon circulation actually, and it can be confirmed in researches.