Seasonal and interannual drought responses in urban vegetation in Santa Barbara, California
Topics: Remote Sensing
, Urban Geography
, Climatology and Meteorology
Keywords: drought, urban, California, Landsat, hyperspectral, remote sensing, tree, grass
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 08:00 AM (Eastern Time (US & Canada)) - 2/25/2022 09:20 AM (Eastern Time (US & Canada))
Room: Virtual 1
Authors:
David L Miller, University of California Berkeley
Michael Alonzo, American University
Susan K Meerdink, University of Iowa
Michael A Allen, University of California Santa Barbara
Christina L Tague, University of California Santa Barbara
Dar A Roberts, University of California Santa Barbara
Joseph P McFadden, University of California Santa Barbara
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Abstract
Many of the key benefits of urban vegetation, including cooling and shading, can become limited as plants are impacted by droughts, and these physiological responses to drought can develop at an array of time scales depending on vegetation type. While many studies have evaluated the response of vegetation to interannual droughts, few have also evaluated drought impacts by season, which is of particular importance for cities that regularly experience seasonal drought (e.g., Mediterranean climates). Here, we quantified the effects of seasonal and interannual drought in the major urban vegetation types in Santa Barbara, California. Multiple remote sensing indices were used to characterize the impacts of drought on vegetation. We used Landsat satellite imagery from 2010-2019 to assess monthly changes in vegetation greenness (NDVI) and relative cooling of vegetation compared to impervious surfaces (ΔLST). We also used repeat airborne hyperspectral imagery from 2013-2015 to track seasonal changes in canopy water content and leaf area via equivalent water thickness. During drought years and in dry summers, vegetation canopy was less green (lower NDVI) and had much warmer surface temperatures (higher ΔLST). Canopy water content provided additional information by showing seasonal adjustments in vegetation that were not as apparent in the NDVI. We found distinct seasonal expressions of drought response among the different vegetation, including trees (e.g., Eucalyptus and coast live oak) and grasses (e.g., irrigated turfgrass, annual grasses), and correlation analysis with a multitemporal drought index (SPEI) further disentangled the overlapping effects of drought time scales on vegetation.
Seasonal and interannual drought responses in urban vegetation in Santa Barbara, California
Category
Virtual Paper Abstract
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