Indications of the hydrogen and oxygen isotopes in precipitation for climate change in Huanglong, Sichuan

The slope and constant of the meteoric water line in Huanglong are both smaller than the global meteoric waterline, which is related to the evaporation enrichment of heavy isotopes as raindrops fall in unsaturated atmosphere, and the climate in Huanglong has been getting warmer and drier in the recent decades. The notable amount effect of the isotopes in precipitation illustrates the vapor in Huanglong precipitation is mainly from low latitude ocean. The seasonal variation in the excess deuterium and the amount effect of the hydrogen and oxygen isotopes in precipitation reflect slight precipitation and strong evaporation and thus strong enrichment of heavy isotopes in dry season of Huanglong with the dry air for being influenced by continental air mass. It is influenced by low latitude marine vapor with moist air, heavy precipitation and slight evaporation in rainy season, so the enrichment of heavy isotopes is slight and the rainfall is characterized with low stable isotopic ratio. Therefore, it can be deduced that the amount effect of the isotopes in precipitation is resulted by the difference in vapor origin; the temperature effect is not notable in Huanglong where the monsoon climate effect restrained and covered up the temperature effect.