Abstract This study investigates the potential effects of historical deforestation in South America using a regional climate model driven with reanalysis data. Two different sources of data were used to quantify deforestation during the 1980s to 2010s, leading to two scenarios of forest loss: smaller but spatially continuous in scenario 1 and larger but spatially scattered in scenario 2. The model simulates a generally warmer and drier local climate following deforestation. Vegetation canopy becomes warmer due to reduced canopy evapotranspiration, and ground becomes warmer due to more radiation reaching the ground. The warming signal for surface air is weaker than for ground and vegetation, likely due to reduced surface roughness suppressing the sensible heat flux. For surface air over deforested areas, the warming signal is stronger for the nighttime minimum temperature and weaker or even becomes a cooling signal for the daytime maximum temperature, due to the strong radiative effects of albedo at midday, which reduces the diurnal amplitude of temperature. The drying signals over deforested areas include lower atmospheric humidity, less precipitation, and drier soil. The model identifies the La Plata basin as a region remotely influenced by deforestation, where a simulated increase of precipitation leads to wetter soil,more »
Temperature Gradients and Inversions in a Forested Cascade Range Basin: Synoptic‐ to Local‐Scale Controls
Cold‐air pooling and associated air temperature inversions are important features of mountain landscapes, but incomplete understanding of their controlling factors hinders prediction of how they may mediate potential future climate changes at local scales. We evaluated how topographic and forest canopy effects on insolation and local winds altered the expression of synoptic‐scale meteorological forcing on near‐surface air temperature inversions and how these effects varied by time of day, season, and spatial scale. Using ~13 years of hourly temperature measurements in forest canopy openings and under the forest canopy at the H.J. Andrews Experimental Forest in the western Cascade Range of Oregon (USA), we calculated air temperature gradients at the basin scale (high vs. low elevation) and at the cross‐valley scale for two transects that differed in topography and forest canopy cover. ERA5 and NCEP NCAR R1 reanalysis data were used to evaluate regional‐scale conditions. Basin and cross‐valley temperature inversions were frequent, particularly in winter and often persisted for several days. Nighttime inversions were more frequent at the cross‐valley scale but displayed the same intra‐annual pattern at the basin and regional scales, becoming most frequent in summer. Nighttime temperature gradients at basin and cross‐valley scales responded similarly to regional‐scale controls, particularly more »
- Award ID(s):
- 2025755
- Publication Date:
- NSF-PAR ID:
- 10449306
- Journal Name:
- Journal of Geophysical Research: Atmospheres
- Volume:
- 125
- Issue:
- 23
- ISSN:
- 2169-897X
- Publisher:
- DOI PREFIX: 10.1029
- Sponsoring Org:
- National Science Foundation
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