Incorporation of CO exchange processes into a multilayer atmosphere-soil-vegetation model

Nagai, Haruyasu

Journal of Applied Meteorology, 44(10), p.1574 - 1592, 2005/10

This paper describes the incorporation of CO exchange processes into an atmosphere-soil-vegetation model SOLVEG and examination of its sensitivity and impact of its stomatal resistance calculation on the latent heat flux over a winter wheat field. The model framework for the heat and water exchanges between the atmosphere and ground surface was validated in the previous papers (Nagai 2002, 2003). In this study, CO exchange processes are incorporated in the model and the performance is examined. In the test calculation, the model simulated the CO flux at 2 m above the ground well as a whole. A sensitivity test to clarify uncertainties for the model settings and parameters showed that the CO production in the soil is the most important factor for the CO calculation. Also, the impact of the CO processes on the latent heat flux is discussed. The results indicate that the new model is effective and preferable to study surface exchanges of heat and water as well as CO.

Atmosphere-soil-vegetation model including CO exchange processes; SOLVEG2

Nagai, Haruyasu

JAERI-Data/Code 2004-014, 92 Pages, 2004/11

JAERI-Data-Code-2004-014.pdf:11.03MB

A new atmosphere-soil-vegetation model named SOLVEG2 (SOLVEG version 2) was developed to study the heat, water, and CO exchanges between the atmosphere and land-surface. The model consists of one-dimensional multilayer sub-models for the atmosphere, soil, and vegetation. It also includes sophisticated processes for solar and long-wave radiation transmission in vegetation canopy and CO exchanges among the atmosphere, soil, and vegetation. The model can be also used by coupling with a three-dimensional atmosphere model. In this paper, details of SOLVEG2, which includes the function of coupling with atmosphere model MM5, are described.

Validation and sensitivity analysis of a new atmosphere-soil-vegetation model, 2; Impacts on in-canopy latent heat flux over a winter wheat field determined by detailed calculation of canopy radiation transmission and stomatal resistance

Nagai, Haruyasu

Journal of Applied Meteorology, 42(3), p.434 - 451, 2003/03

This paper describes the improvement of an atmosphere-soil-vegetation model and the validation of the new model by observation. In the previous performance test using measured data, some limitations were revealed in the schemes for the canopy radiation transmission and the stomatal resistance calculation, and are improved in this study. By these improvements, the observed albedo and latent heat flux are simulated more properly than before. Results of comparisons between calculations and observations for a winter wheat field and a grassland indicate that the predictability and applicability are improved by the introduction of the new schemes.

Leaf surface wetness measurements on Norway spruce

Held, A.*; Katata, Genki

no journal, , 

Leaf surface wetness is an important factor in meteorological, agricultural, and environmental studies of plant-atmosphere exchange processes. Here, we present leaf wetness measurements using electrical sensors clipped directly to Norway spruce needles, and deposition estimates of inorganic ions to Norway spruce needles determined by a leaf-washing technique. The measurements were carried out at the Waldstein ecosystem research site of the University of Bayreuth. Leaf surface wetness was compared with relative humidity and wind speed, two key meteorological controls of leaf surface wetness. Finally, a trial calculation of the multi-layer atmosphere-soil-vegetation model SOLVEG was compared with the observed data. Overall, leaf surface wetness affects diverse phenomena such as vegetation-atmosphere water exchange or deposition fluxes to vegetation surfaces, which must be further explored in interdisciplinary research projects.