Moist Land Research Articles

Potential impacts of human-induced land cover change on East Asia monsoon

As one major performance of anthropogenic activities, human-induced land use and land cover changes in East Asia have been one of the largest regions in the world. In the past 3000 years, more than 60% of the region has been affected by conversion of various categories of natural vegetation into farmland, conversion of grassland into semidesert and widespread land degradation. Such human-induced land cover changes result in significant changes of surface dynamic parameters, such as albedo, surface roughness, leaf area index and fractional vegetation coverage, etc. The results of a pair of numerical experiments in this paper have shown that by altering the complex exchanges of water and energy from surface to atmosphere, the changes in land cover have brought about significant changes to the East Asian monsoon. These include weakening of the summer monsoon and enhancement of winter monsoon over the region and a commensurate increase in anomalous northerly flow. These changes result in the reduction of all components of surface water balance such as precipitation, runoff, and soil water content. The consequent diminution of northward and inland moisture transfer may be a significant factor in explaining the decreasing of atmospheric and soil humidity and thus the trend in aridification observed in many parts of the region, particularly over Northern China during last 3000 years. The variation of East Asia monsoon presented here is the result of land cover changes only. It is very likely that the anthropogenic modification of monsoon system would have been occurred in the long history of civilization.

Synergistic feedbacks from ocean and vegetation on the African Monsoon response to Mid‐Holocene insolation

We used a coupled ocean‐atmosphere General Circulation Model without flux corrections, iteratively coupled to a biome model, to explore the impact of vegetation and ocean feedbacks on mid‐Holocene monsoon change in northern Africa. We show that both feedbacks significantly increase the northward penetration and the intensity of the monsoon rainfall. The major contribution of the ocean is to enhance the inland moisture advection, whereas that of vegetation is to increase local recycling. Synergistic interactions between ocean and vegetation feedbacks play a critical role in the African monsoon changes, yielding to model results in much better agreement with observations.

The Effect of Variations in Surface Moisture on Mesoscale Circulation

Abstract A two-dimensional numerical Model with moist physics is used to simulate circulations induced by horizontal variations in surface-moisture availability. The model contains prognostic equations for water vapor, cloud water, and rain water, with a simple parameterization of cloud microphysical processes. Four geometric variations of surface-moisture availability are examined: 1) an edge geometry which includes a land-water contrast (classic sea breeze) and moist land adjacent to dry land (inland sea breeze), 2) a single strip of moist land surrounded by dry land 3) alternating bands of moist and dry land, and 4) a single strip of dry land surrounded by moist land. For convectively unstable initial conditions with a relative humidity of 50%, lifting associated with the sea-breeze front induces a precipitation system which propagates inland from the coast. The sea-breeze circulation associated with dry land is considerably stronger than that produced by moist land; however, the evaporation over land ...

The effect of soil moisture on circulation and rainfall in a tropical model

AbstractThe sensitivity of a tropical model to soil moisture content has been investigated using a simplified version of the UK Meteorological Office 11‐layer model. the model area represented a zonally‐symmetric version of West Africa. the results of one experiment (D) with a desert in the same latitudes as the Sahara were compared with those of another experiment (W) in which the desert was replaced by moist land. the initial fields contained an idealized easterly wave which developed during the experiments to form depressions whose movement, structure and associated rainfall were strongly influenced by the dryness of the underlying surface. the energetics of these disturbances were analysed and two distinct mechanisms for maintaining their eddy kinetic energy are proposed, depending on the soil moisture.Results from W suggest that once the land was moist it maintained itself in this state for at least several weeks. In D, however, the initial aridity north of 14°N was sustained, suggesting that ground dryness alone can cause deserts to persist. an analysis of observed rainfall data for the northern Sahel provides much stronger evidence for the persistence of rainfall anomalies from year to year than do similar analyses for the southern Sahel. the possibility that soil moisture anomalies could contribute to this persistence is briefly discussed.

Significance of Lipoperoxides in Gastric Cancer

AbstractThe “lipoperoxide hypothesis” proposed by the author, according to which cancer is generated by oxidized lipids accumulated in a living body, is valuable in understanding following phenomena in gastric cancer: decrease in the secretion of hydrochloric acid to gastric juice; relatively frequent occurrence of gastric cancer amongst people who take smoked, baked or dried fish and who live in a low and moist land or in an acidic soil region; gastric cancer often originates from gastric ulcer; males suffer more from this disease than females.

Control of Four Smut Diseases by Regulation of Planting Method under Irrigation

ANOMALOUS amounts of disease in supposedly exactly repeated experiments of flag smut of wheat, and previously with covered smut of barley1, were eventually traced to difference in planting method. Under irrigation in Egypt, these cereals are either broadcast on moist land and ploughed in (herati method) or broadcast on dry land, harrowed in with a wooden baulk and irrigated (afir method).