Shifting dry spells in Central Chile: Implications for agricultural water planning

Abstract
Chile's agricultural production occurs in a highly variable Mediterranean climate and faces declining annual precipitation trends as well as growing competition from other uses. Water availability for agriculture depends on winter precipitation; however, a more even distribution of precipitation throughout the year would better support agricultural planning and management. We examine the occurrence, frequency, and trends of dry spells in Central Chile (32°–40° S) as a proxy for changes in the timing of dry‐wet seasons, using a gridded daily precipitation dataset spanning the period from 1960 to 2021. Our results indicate a significant increase in dry spells (+1 event/decade), but shorter (−2 days/event), and a significant decrease in precipitation per wet spell (−2 mm/event/decade). Findings suggest that changes in dry spells should also be considered in planning and policy, as some regions may be experiencing water shortages due to shifts in timing and access, rather than simply having less water.

Core Ideas

Changes in the length and timing of dry and wet spells impact seasonal precipitation.

Changes in dry spells introduce more uncertainty to agricultural planning in Central Chile.

Dry spells analysis complements other annual precipitation deficit indices.