Discontinuity in the Vertical Profile of Water Vapor Density at Hot, Dry Soil Surfaces.

Kobayashi, Tetsuo; He, Wenjun; Nagai, Hideyuki; Adachi, K.

doi:10.3178/jjshwr.9.438

Cited by 2 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the same time, convection occurs not only above the surface but also in the dry, soil surface layer (DSL) (Kobayashi et al, 1996;Nagai et al, 1997;Kobayashi et al, 1998). As a result of these processes, water vapor density increases sharply from just under the soil surface to the surface air layer immediately above it.…”

Section: Introductionmentioning

confidence: 99%

“…As a result of these processes, water vapor density increases sharply from just under the soil surface to the surface air layer immediately above it. Nevertheless, the vapor moves upward across the surface against its density gradient (Kobayashi et al, 1996). Thus, under dry conditions, the Ohm's law analogy or the bulk scheme widely used (Ye and Pielke, 1993) is not strictly rational to formulate the latent heat flux at the surface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Rational Parameterization of Evaporation from Dry, Bare Soil

Kobayashi

1998

Journal of the Meteorological Society of Japan

Self Cite

View full text Add to dashboard Cite

The evaporation of water from bare soil changes in mechanism as well as in magnitude as the surface dries. This evaporation proceeds in three stages, the third of which has a mechanism completely different from the other two stages. Therefore, only the parameterization schemes for soil-surface evaporation that take account of this stage switching should be considered as rational.A rational parameterization of the soil-surface evaporation based on a three-layer model of the vertical distribution of soil moisture is proposed. Each stage of evaporation is characterized by one of the three soil layers that comes to the surface. The switching from one stage to another can be determined from the difference between surface soil temperature and screen-level air temperature. The evaporation rate in the first stage is equal to the potential evaporation rate Ep, and that in the second stage can be expressed by the product of Ep and "surface moisture availability" M, which depends on the wetness of the superficial layer of soil and the soil type. Since these are practically the same as the existing parameterizations, only a general idea of formulating the two stages is given in this paper. The third-stage process, however, is formulated by a newly invented scheme that will be called the "DSL bulk method." An example of the application of this method to the Tottori-Dune sand is also shown. This parameterization makes it possible to evaluate the evaporation rate in the third stage by the surface soil temperature and the average water content for the top 5cm of soil, and both can be measured by remote sensing.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%