Inferring Scalar Sources and Sinks Within Canopies Using Forward and Inverse Methods

Abstract

It is becoming clear that the description of water exchange over vegetated surfaces can bene t from a simultaneous consideration of heat and C O 2 exchanges, as all these exchange processes are intertwined at the most fundamental level. Over the last two decades, several approaches have been developed to infer scalar sources and sinks within canopies without resorting to gradient-di usion theory. This study investigates recent developments in multi-layer methods to compute distributions and strengths of scalar sources and sinks within the canopy volume. Two types of model formulations are considered: 1 forward methods which require vertical foliage distribution along with canopy radiative, physiological, biochemical, and drag properties and 2 inverse methods which require measured mean scalar concentration distribution within the canopy. These approaches are able to reproduce measured turbulent uxes above the canopy without relying on an empirical relationship between turbulent scalar uxes and mean concentration gradients. However, both approaches share the need for accurate description of the second moments of the velocity statistics inside the canopy.

Simulated Diurnal Cycles and Seasonal Variability of Low‐Level Jets in the Boundary Layer over Complex Terrain on the Coast of Southeast China

“…The WRF‐ARW (Katul et al, ; Skamarock et al, ; Wang et al, ) and CALMET (Wesson et al, ) models are used in this study. The WRF‐ARW is a nonhydrostatic, fully compressible, primitive equation model produced by the National Center for Atmospheric Research (NCAR), Air Force Weather Agency, National Oceanic and Atmospheric Administration, and other governmental agencies and universities.…”