PAIRED SUB-ANNUAL BIOMARKER AND ELEMENTAL CLIMATE PROXIES REVEAL MONTHS OF CLIMATE SIGNAL INTEGRATION IN THE ARABIAN SEA

Summary Laminated Pakistan Margin (northeastern Arabian Sea) marine sediments provide excellent, continuous archives of past climate conditions that can be used to reconstruct the variability of the Southwest (summer) and Northeast (winter) monsoons of India. Sea surface temperatures (SSTs) were reconstructed using UK'37 and CCaT proxies, with a resolution of 0.1-year. Both proxies reconstruct reasonable SSTs compared to the instrumental range, but neither proxy captures the full ∼6°C annual cycle. However, there is coherence on interannual to decadal timescales between instrumental SSTs and proxy-derived SSTs, indicating the proxies capture the same climatic cyclicity as instrumental SSTs. In particular, the UK'37 and instrumental SSTs have similar interannual to decadal trends, which is apparent when comparing UK'37 SSTs with an 11-month moving mean of the instrumental SSTs. The proxy SST signal is a temporal integration of SSTs from up to several months. We posit that this may be linked to variable sinking flux throughout the year. The sinking flux of these organisms increases during periods of high productivity (spring-summer, winter) or high lithogenic flux. These organisms likely remain in suspension when sinking flux is low, which may last several months; subsequent aggregation then integrates their SST signals.