edu.ucar.opensky::articles:21597 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T16:03:14.090761 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7n300qg https://doi.org/10.17190/AMF/1246061 https Related Dataset #1 AmeriFlux US-Ho1 Howland Forest (main tower) https://doi.org/10.17190/AMF/1246088 https Related Dataset #2 AmeriFlux US-NR1 Niwot Ridge Forest (LTER NWT1) A comparison of the Diel cycle of modeled and measured latent heat flux during the warm season in a Colorado subalpine forest 2018-03-01T00:00:00Z publication https://n2t.org/ark:/85065/d7n300qg https://doi.org/10.1002/2017MS001248 Burns, Sean author Swenson, Sean author Wieder, William author Lawrence, David M. author Bonan, Gordon B. author Knowles, J. F. author Blanken, P. D. author UCAR/NCAR - Library publisher Precipitation changes the physiological characteristics of an ecosystem. Because land-surface models are often used to project changes in the hydrological cycle, modeling the effect of precipitation on the latent heat flux lambda E is an important aspect of land-surface models. Here we contrast conditionally sampled diel composites of the eddy-covariance fluxes from the Niwot Ridge Subalpine Forest AmeriFlux tower with the Community Land Model (CLM, version 4.5). With respect to measured lambda E during the warm season: for the day following above-average precipitation, lambda E was enhanced at midday by approximate to 40 W m(-2) (relative to dry conditions), and nocturnal lambda E increased from approximate to 10 W m(-2) in dry conditions to over 20 W m(-2) in wet conditions. With default settings, CLM4.5 did not successfully model these changes. By increasing the amount of time that rainwater was retained by the canopy/needles, CLM was able to match the observed midday increase in lambda E on a dry day following a wet day. Stable nighttime conditions were problematic for CLM4.5. Nocturnal CLM lambda E had only a small (approximate to 3 W m(-2)) increase during wet conditions, CLM nocturnal friction velocity u(*) was smaller than observed u(*), and CLM canopy air temperature was 2 degrees C less than those measured at the site. Using observed u(*) as input to CLM increased lambda E; however, this caused CLM lambda E to be increased during both wet and dry periods. We suggest that sloped topography and the ever-present drainage flow enhanced nocturnal u(*) and lambda E. Such phenomena would not be properly captured by topographically blind land-surface models, such as CLM. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2018 Author(s). This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. None eng geoscientificInformation