iGCM模拟全球典型站点降水中δ18O的效果评价以及香港站δ18O年际震荡的原因探讨

The performance evaluation for δ18O in precipitation simulated by iGCM of global typical station and investigating the reasons of δ18O inter-annual oscillation in Hongkong station

为了评价不同的稳定同位素大气环流模式（iGCM）在不同气候区的适用性，利用8个水稳定同位素大气环流模式（CAM2、ECHAM4、GISSE-F、HADAM3、ISOGSM、LMDZ4、GISSE-N和MUGCM）的数据和全球降水同位素监测网（GNIP）的实测数据，分析了全球13个气候大区（高山高原、热带季风、热带雨林、热带海洋、热带草原、地中海、亚热带湿润、亚热带季风、温带海洋、温带大陆性干旱、温带大陆性、亚寒带针叶林和寒带冰原气候）的典型站点降水中δ18O的季节变化，评价了模式的月数据相对于GNIP实测数据的模拟效果。结果表明，LMDZ4、GISSE-N和ECHAM3这3个模式的整体模拟效果较好，且不同站点降水中δ18O的季节变化原因可以从不同季节水汽来源的差异和水汽在输送过程中降水量的季节差异来分析。为了深入分析单站降水中δ18O的年际变化，利用香港站的长时间序列数据分析了降水中δ18O的年际变化与大气环流异常的关系，并对实测和模拟结果进行了分析。结果表明，ECHAM4和LMDZ4这两个模式能够模拟出香港站降水中δ18O与南方涛动指数（SOI）的负相关关系。通过分析1998年和1999年大气环流异常对香港站降水中δ18O的影响，得出水汽来源的年际变化以及水汽输送带上游地区降水的多寡可能是造成香港地区降水中δ18O年际变化的主要原因。

In order to evaluate the applicability of different atmospheric circulation modes in different climate zones, the data of eight water stable isotope atmospheric circulation models （CAM2, ECHAM4, GISSE-F, HADAM3, ISOGSM, LMDZ4, GISSE-N and MUGCM）and the measured data of GNIP were used to analyse the seasonal variations of δ18O in precipitation from 13 typical climate stations in the world. These climate zones are alpine plateau climate, tropical monsoon climate, tropical rainy climate, tropical marine climate, tropical savanna climate, etesian climate, subtropical humid climate, subtropical monsoon climate, temperate marine climate, temperate continental climate, temperate continental humid climate, subfrigid coniferous forest climate and cold ice climate respectively. What＇s more, the simulation performance between the monthly model data and the measured data of GNIP was evaluated. The analytical results indicated that the three models including LMDZ4, GISSE-N and ECHAM4 have good overall simulation performance. The reasons for seasonal variations of δ18O in precipitation from different stations can be analyzed from the difference of vapor sources during different seasons and the seasonal difference of precipitation during vapor transportation. To analysis the annual variation of δ18O in precipitation from the single station deeply, we used long sequence data from Hongkong to analyse the relationship between the inter-annual variation of δ18O in precipitation and the abnormal atmospheric circulation. The measured data and the simulation results was also analysed. The results indicated that the two models, ECHAM4 and LMDZ4, can simulate the negative correlation between annual δ18O in precipitation from Hongkong station and corresponding southern oscillation index （SOI）. After the analysis of effects about δ18O in precipitation from Hongkong station which was the result of abnormal atmospheric circulation during 1998 and 1999, we can come to the conclusion that the source variation of inter-annual vapor and precipitation variation of upstream area on the vapor transporting channel are the main reasons for inter-annual variation of δ18O in precipitation from Hongkong area.