Abstract
Summer precipitation in Hawai'i accounts for 40% of the annual total and provides important water sources. However, our knowledge about its variability remains limited. Here we show that statewide Hawai'i summer rainfall (HSR) variability exhibits two distinct regimes: quasi-biennial (QB, ~2 years) and interdecadal (~30–40 years). The QB variation is linked to alternating occurrences of the Western North Pacific (WNP) cyclone and anticyclone in successive years, which is modulated by the intrinsic El Niño–Southern Oscillation biennial variability and involves a positive feedback between atmospheric Rossby waves and underlying sea surface temperature (SST) anomalies. The interdecadal variation of HSR is largely modulated by the Pacific Decadal Oscillation through affecting upstream low-level humidity that affects topographic rainfall. HSR shows weak long-term drying trend during 1920–2019. This first description of the major physical drivers of summer rainfall variability provides key information for seasonal rainfall prediction in Hawai'i.
| Original language | English |
|---|---|
| Article number | e2020GL091260 |
| Journal | Geophysical Research Letters |
| Volume | 47 |
| Issue number | 23 |
| DOIs | |
| State | Published - Dec 16 2020 |
| Externally published | Yes |
Funding
X. L. and B. W. acknowledge the support from National Science Foundation (Climate Dynamics Division) Award # AGS‐1540783. X. L. gratefully acknowledges support from the Water Resources Research Center (WRRC) and the Joint Institute for Marine and Atmospheric Research (JIMAR). A. F. is thankful for the support of the Pacific Islands Climate Adaptation Science Center (PI‐CASC), Award Number G19PG00021. Giambelluca's contribution was supported by Hawai'i EPSCoR Program (NSF) award OIA‐1557349, Pacific Islands Climate Adaptation Science Center (USGS) award G18A00021, and the Pacific RISA Program (NOAA). This paper is the IPRC publication #1486, SOEST publication #11188, and ESMC publication #334. X.?L. and B.?W. acknowledge the support from National Science Foundation (Climate Dynamics Division) Award # AGS-1540783. X.?L. gratefully acknowledges support from the Water Resources Research Center (WRRC) and the Joint Institute for Marine and Atmospheric Research (JIMAR). A.?F. is thankful for the support of the Pacific Islands Climate Adaptation Science Center (PI-CASC), Award Number G19PG00021. Giambelluca's contribution was supported by Hawai'i EPSCoR Program (NSF) award OIA-1557349, Pacific Islands Climate Adaptation Science Center (USGS) award G18A00021, and the Pacific RISA Program (NOAA). This paper is the IPRC publication #1486, SOEST publication #11188, and ESMC publication #334.
Keywords
- ENSO
- Hawai'i rainfall variability
- Pacific Decadal Oscillation (PDO)
- Quasi-Biennial Oscillation
- rainfall trend
- western North Pacific high