| 01 Jun 2026
Westward extension of ENSO teleconnections links spring rainfall between northern Southeast Asia and the Arabian Peninsula
Abstract. ENSO teleconnections are not stationary, but how this nonstationarity reorganizes spring hydroclimate across Asia remains unclear. Spring rainfall is particularly important for the Arabian Peninsula, one of the world’s most arid regions, where even modest rainfall changes can affect water availability and drought risk. Here we show that a March–April rainfall seesaw between the Arabian Peninsula and northern Southeast Asia strengthened markedly after the late 1990s. During 1979–1998, ENSO-related convection and circulation anomalies remained mainly confined to the tropical Pacific–Maritime Continent sector and projected only weakly toward the Arabian Peninsula, with limited evidence of a coherent pathway linking the two regions. During 1999–2023, the ENSO-related response extended farther westward and northwestward, linking El Niño-related suppressed convection and reduced rainfall over northern Southeast Asia with enhanced rainfall over the Arabian Peninsula. This shift was associated with a reorganization of Indo-Pacific overturning, including a more distinct double-cell Walker response, a strengthened Arabian Peninsula vertical branch extending farther northward, and enhanced upper-level Rossby-type and thermal adjustment. Idealized model experiments show that western equatorial Indian Ocean heating can generate an Arabian Peninsula-sector response and that this response becomes more effective under the later-period background state. Observed changes in convection, low-level pressure and winds, and the upper-level jet and divergence further indicate that the later-period ENSO anomalies developed within a modified mean-state environment. These results identify a nonstationary ENSO teleconnection pathway in which the westward extension of tropical heating anomalies, Walker–Hadley coupling, and off-equatorial upper-level adjustment connect spring rainfall variability across Southeast and West Asia.
General Comments.
The manuscript examines ENSO teleconnections for spring rainfall over Southeast (SE) Asia and the Arabian Peninsular (AP) in two time periods, from 1979-1998 and 1999-2023. The authors propose a shifting dynamical pathway which enhances the relationship between suppressed SE Asia rainfall and increased AP rainfall during El Nino. The authors carry out idealised experiments prescribing warming in the Indian Ocean to test the sensitivity of the AP response to a changing background climate. I found most of the manuscript to be clear and well-written with good descriptive figure captions. However, when I got to the idealised model discussion and conclusions I found it difficult to piece together those components. I think the manuscript makes some interesting points and would provide additional insight into changing ENSO teleconnection if published. However, the current manuscript could benefit from additional introductory figures, some additional attention to some of the statements supported by the supplemental figures, and a bit more clarity about how the idealised simulations support the conclusions. Many of my comments are probably easily addressed, but because of the quantity of my suggestions and because some relate to the interpretation and statistical significance of the results, I’d recommend major revisions. Find my comments below.
Specific comments
- Can the authors be clearer in this section about which latitudinal portions you are referring to? For example, the text refers to the AP-sector response being ‘clearer’ in P2 (Line 366). From Fig S5, the P2 responses seem relatively weak. Is this referring to the small area of ascent on the northern boundary of AP? It’s not clear to me from the text.
- Overall, the changes discussed seem to indicate a reduced descent response, as opposed to a particularly enhanced ascent response which is implied in the text.
- I note that the hatching is different from Fig S5 bottom panels and Fig 3b;c when it seems the same quantities are plotted. Why are these different?
Minor/Technical Comments.