Monsoon Asia Drought Atlas Research Articles

Links between Indo-Pacific climate variability and drought in the Monsoon Asia Drought Atlas

Drought patterns across monsoon and temperate Asia over the period 1877–2005 are linked to Indo-Pacific climate variability associated with the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). Using the Monsoon Asia Drought Atlas (MADA) composed of a high-resolution network of hydroclimatically sensitive tree-ring records with a focus on the June–August months, spatial drought patterns during El Niño and IOD events are assessed as to their agreement with an instrumental drought index and consistency in the drought response amongst ENSO/IOD events. Spatial characteristics in drought patterns are related to regional climate anomalies over the Indo-Pacific basin, using reanalysis products, including changes in the Asian monsoon systems, zonal Walker circulation, moisture fluxes, and precipitation. A weakening of the monsoon circulation over the Indian subcontinent and Southeast Asia during El Niño events, along with anomalous subsidence over monsoon Asia and reduced moisture flux, is reflected in anomalous drought conditions over India, Southeast Asia and Indonesia. When an IOD event co-occurs with an El Niño, severe drought conditions identified in the MADA for Southeast Asia, Indonesia, eastern China and central Asia are associated with a weakened South Asian monsoon, reduced moisture flux over China, and anomalous divergent flow and subsidence over Indonesia. Insights into the relative influences of Pacific and Indian Ocean variability for Asian monsoon climate on interannual to decadal and longer timescales, as recorded in the MADA, provide a useful tool for assessing long-term changes in the characteristics of Asian monsoon droughts in the context of Indo-Pacific climate variability.

Repurposing climate reconstructions for drought prediction in Southeast Asia

Climate information may help smallholder farmers in Southeast Asia takeinformed risks and reduce their climate vulnerability. Model-based seasonalforecasts are limited in the skill they offer with longer lead times, and intheir accessibility to farmers in remote regions. Climate reconstructions derivedfrom tree rings can complement model-based forecasts, providing probabilisticestimates of future climate at an annual resolution. This study demonstratesthe skill of PDSI reconstructions derived from the Monsoon Asia DroughtAtlas (MADA) to forecast a climate signal several years into the future, andillustrates the advantage of such information vis-a-vis the simple strategy ofassuming climate to persist from year to year. This work shows the potentialfor such climate reconstructions to improve inter-annual decisions on SoutheastAsian farms, and highlights the social research necessary to transmute thispotential into a valuable climate decision aid.In much of Southeast Asia the capacity of smallholder farmers to predict andprotect against drought is limited. Farmers commonly employ conservative, risk-averse strategies to farm planning and operation that reduce losses to climate-relateddamages, but that also reduce surpluses in years of favorable climate (Meinke andStone 2005). Farmers operating close to thresholds of sustenance and self-sufficiencywho fail to take advantage of these rents can fall into ‘poverty traps’ (Holling 2001;Sachs 2005), unable to lift themselves from degraded land conditions and a lackof capital. To help smallholders become informed risk takers and capitalize on the