Asymmetric Impacts of Indian Ocean Dipole on Summer Climate Over Arabian Peninsula

Abstract While the Indian Ocean Dipole (IOD) influences the Arabian Peninsula (AP) summer climate, the underlying mechanisms remain unclear. Here, we show the IOD's impact is asymmetric, with negative IOD events driving stronger, opposite climate anomalies to positive IOD events. Positive IOD modulates the local Hadley circulation and the South Asian High, establishing a lower‐level anticyclone over the AP. This anomalous circulation drives a dipole surface air temperature pattern (warmer south, slightly cooler north) via altered horizontal advection. It also suppresses southwestern AP precipitation through weakened ascent and reduced moisture influx. The stronger negative IOD response is attributed to distinct factors: for temperature, nonlinear advection and enhanced cloud‐radiation feedback; for precipitation, a “floor effect” from low mean‐state precipitation limits further drying during positive IOD. Clarifying these mechanisms provides a new framework for understanding and predicting climate in this vulnerable region.