Latent heat

About: Latent heat is a research topic. Over the lifetime, 13503 publications have been published within this topic receiving 302811 citations.

Evaluation of the NCEP Global Forecast System at the ARM SGP Site

Abstract: This study evaluates the performance of the National Centers for Environmental Prediction Global Forecast System (GFS) against observations made by the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program at the southern Great Plains site for the years 2001–04. The spatial and temporal scales of the observations are examined to search for an optimum approach for comparing grid-mean model forecasts with single-point observations. A single-column model (SCM) based upon the GFS was also used to aid in understanding certain forecast errors. The investigation is focused on the surface energy fluxes and clouds. Results show that the overall performance of the GFS model has been improving, although certain forecast errors remain. The model overestimated the daily maximum latent heat flux by 76 W m−2 and the daily maximum surface downward solar flux by 44 W m−2, and underestimated the daily maximum sensible heat flux by 44 W m−2. The model’s surface energy balance was reached by a ca...

Climatic features of atmospheric heat source/sink over the Qinghai-Xizang Plateau in 35 years and its relation to rainfall in China

Abstract: Using the 1961–1995 monthly averaged meteorological data from 148 surface stations in the Qinghai-Xizang Plateau (QXP) and its surrounding areas, calculation of the 35-year atmospheric heat source/sink ( ) and an analysis on its climatic features and relation to rainfall in China have been made. It is found that on the average, the atmospheric heat source over the QXP is the strongest in June (78 W / m2) and cold source is the strongest in December (−72 W/m2). The sensible heat of the surface increases remarkably over the southwest of the QXP, causing the obvious increase of there in February and March, which makes a center of the atmospheric heat source appear over the north slope of the Himalayas. Afterwards, this center continues to intensify and experiences noticeable migration westwards twice, separately occurring in April and June. The time when the atmosphere over the east of the QXP becomes heat source and reaches strongest is one month later than that over the southwest of the QXP. In summer, the latent heat of condensation becomes a heating factor as important as the sensible heat and is also a main factor that makes the atmospheric heat source over the east of the QXP continue growing. On the interdecadal time scale, (Q1) of the QXP shows an abrupt change in 1977 and a remarkable increase after 1977. The atmospheric heat source of the spring over the QXP is a good indicator for the subsequent summer rainfall over the valleys of the Changjiang and Huaihe rivers and South China and North China. There is remarkable positive correlation between the QXP heat source of summer and the summer rainfall in the valleys of the Changjiang River.

Simulated Seasonal and Interannual Variability of the Mixed Layer Heat Budget in the Northern Indian Ocean

Abstract: A global ocean general circulation model (OGCM) is used to investigate the mixed layer heat budget of the northern Indian Ocean (NIO). The model is validated against observations and shows fairly good agreement with mixed layer depth data in the NIO. The NIO has been separated into three subbasins: the western Arabian Sea (AS), the eastern AS, and the Bay of Bengal (BoB). This study reveals strong differences between the western and eastern AS heat budget, while the latter basin has similarities with the BoB. Interesting new results on seasonal time scales are shown. The penetration of solar heat flux needs to be taken into account for two reasons. First, an average of 28 W m 2 is lost beneath the mixed layer over the year. Second, the penetration of solar heat flux tends to reduce the effect of solar heat flux on the SST seasonal cycle in the AS because the seasons of strongest flux are also seasons with a thin mixed layer. This enhances the control of SST seasonal variability by latent heat flux. The impact of salinity on SST variability is demonstrated. Salinity stratification plays a clear role in maintaining a high winter SST in the BoB and eastern AS while not in the western AS. The presence of freshwater near the surface allows heat storage below the surface layer that can later be recovered by entrainment warming during winter cooling (with a winter contribution of 2.1°C in the BoB). On an interannual time scale, the eastern AS and BoB are strongly controlled by the winds through the latent heat flux anomalies. In the western AS, vertical processes, as well as horizontal advection, contribute significantly to SST interannual variability, and the wind is not the only factor controlling the heat flux forcing.