Comparison of Proxy and Multi-Model Ensemble Means on Volcanic Aerosols'
Hydrological Effects in Asian Monsoon and Westerlies-dominated
Proxy-model comparisons show large discrepancies on volcanic aerosols’
hydrological effects in the Asian monsoon region (AMR). This was mostly
imputed to uncertainties of the single model used in previous studies.
Here, we compared two groups of CMIP5 multi-model ensemble mean (MMEM)
with the tree-ring-based reconstruction Monsoon Asia Drought Atlas (MADA
PDSI), to examine their reliability on reflecting hydrological effects
of the volcanic eruptions in 1300-1850 CE. Time series plots indicate
that MADA PDSI and MMEMs agree on the significant drying effects of
volcanic perturbation over the monsoon-dominated subregion, while
mismatches exist over the westerlies-dominated subregion. Comparisons on
spatial patterns suggest that MADA PDSI and MMEMs agree better in one
year after the volcanic eruption than in the eruption year, and in
subregions with more available tree ring chronologies. MADA PDSI and
CMIP5 MMEMs agree on the drying effect of volcanic eruptions in
western-East Asia, South Asian summer monsoon and northern East Asian
summer monsoon (EASM). Model results suggest significant wetting effect
in southern EASM and western-South Asia, which agrees with the observed
hydrological responses to 1991 Mount Pinatubo eruption. Analysis on LME
model simulations show similar hydrological responses. These results
suggest that CMIP5 MMEM is able to reproduce volcanic eruptions’
hydrological effects in southern AMR.