How well do the existing indices measure the strength of India-Burma Trough? Insight from its relationship with ENSO
编号:31 访问权限:仅限参会人 更新:2025-03-20 08:47:32 浏览:60次 张贴报告

报告开始:2025年04月18日 09:56(Asia/Shanghai)

报告时间:1min

所在会场:[PO] 墙报 [po] 墙报

暂无文件

摘要

The India-Burma Trough (IBT) is a semi-permanent low-pressure trough over the Bay of Bengal that plays a crucial role in modulating weather and climate over East and South Asia. Various indices have been proposed to quantify IBT strength since 1999, but differences in their definitions and data sources have led to inconsistencies in their representation of IBT variability and its large-scale impacts. This study evaluates the effectiveness of existing IBT indices by recalculating them using a uniform dataset and methodology, aiming to assess their ability to capture IBT dynamics and their relationship with ENSO.Using ERA5 reanalysis data, eight IBT indices were recalculated for the winter seasons from 1980 to 2024. Given the presence of strong linear trends in geopotential height-based indices, likely due to global warming, these trends were removed before further analysis. Hierarchical clustering was applied to classify the indices into two categories: (1) wind-field-based indices (e.g., vorticity), and (2) geopotential height-based indices. A representative index from each category was selected and compared through regression analysis against atmospheric circulation fields (geopotential height, vorticity, vertical velocity, and wind fields), precipitation, and temperature. Additionally, the IBT-ENSO relationship was examined through regression analysis with sea surface temperature (SST).Results indicate that wind-field-based indices better capture the IBT’s dynamic structure in circulation fields compared to geopotential height-based indices. Furthermore, the two index categories exhibit significantly different climate impacts, particularly on temperature and precipitation patterns in East and South Asia. Most notably, regression analysis with SST shows that the IBT-ENSO relationship varies depending on the index used: wind-field-based indices indicate that a strong IBT corresponds to an El Niño-like SST pattern, whereas geopotential height-based indices suggest an association with a La Niña-like pattern. This discrepancy suggests that ENSO influences IBT strength primarily through enhanced local cyclonic curvature rather than broad geopotential height changes, which may not directly reflect IBT intensity.These findings underscore the importance of index selection in IBT-related research. While wind-field-based indices appear to provide a more physically consistent representation of IBT dynamics, uncertainties remain due to the varying methodologies used in defining IBT indices. Further research is needed to refine IBT indices and improve their applicability in climate analysis and forecasting.

关键词
India-Burma Trough,ENSO,Precipitation,Clustering
报告人
李靖楠
研究生 云南大学

稿件作者
胡鹏 云南大学
李靖楠 云南大学
发表评论
验证码 看不清楚,更换一张
全部评论
重要日期
  • 会议日期

    04月17日

    2025

    04月21日

    2025

  • 04月10日 2025

    初稿截稿日期

  • 04月20日 2025

    注册截止日期

主办单位
中国科学院大气物理研究所
承办单位
中国科学院大气物理研究所
联系方式
移动端
在手机上打开
小程序
打开微信小程序
客服
扫码或点此咨询