Cumulus (Cu) can transport heat and water vapor from the boundary layer to the free atmosphere, leading to the redistribution of heat and moist energy in the lower atmosphere. This paper uses the fine-resolution CloudSat–CALIPSO product to characterize Cu over the Tibetan Plateau (TP). It is found that Cu is one of the dominant cloud types over the TP in the northern summer. The Cu event frequency, defined as Cu occurring within 50-km segments, is 54% over the TP in the summer, which is much larger over the TP than in its surrounding regions. The surface wind vector converging at the central TP and the topographic forcing provide the necessary moisture and dynamical lifting of convection over the TP. The structure of the atmospheric moist static energy shows that the thermodynamical environment over the northern TP can be characterized as having weak instability, a shallow layer of instability, and lower altitudes for the level of free convection. The diurnal variation of Cu with frequency peaks during the daytime confirms the surface thermodynamic control on Cu formation over the TP. This study offers insights into how surface heat is transported to the free troposphere over the TP and provides an observational test of climate models in simulating shallow convection over the TP.
Based on the International Satellite Cloud Climatology Project (ISCCP) data, and the World Meteorological Organization (WMO) surface synoptic observations, spatial distributions and seasonal variations of total cloudiness and fractional cloud amount of high, middle and low clouds over China are examined. It is found that low clouds mainly appear along the southeast coast of China, middle clouds dominate southern China and high clouds mainly occur over northern China. Seasonal variations of convective clouds over northern China, southern China and the Tibetan Plateau are similar, reaching a maximum in summer and a minimum in winter; whereas the seasonal variation of stratiform clouds displays large spatial variation, with opposite phase in northern and southern China.
BackgroundAcute pharyngitis is frequently seen in primary care. Acute viral pharyngitis may be easily misdiagnosed as acute bacterial pharyngitis. Laboratory-confirmed diagnosis of respiratory viruses is recommended. The purpose of this study was to compare the sensitivities among oropharyngeal swab (OPS), nasopharyngeal swab (NPS), and nasal wash (NW) in adults with acute pharyngitis.MethodsOPS, NPS, and NW were obtained from each participant with acute pharyngitis. The specimens were tested for 15 respiratory viruses by TaqMan real-time polymerase chain reaction. A sample was considered to be a true positive if any of the specimens was positive. The sensitivities among samples were compared by chi-square test or Fisher’s exact test, as appropriate.ResultsOne hundred three triple samples collected consecutively by OPS, NPS, and NW were obtained. In 73 patients, one or more viruses were detected by any of the three methods. Among all viruses, the sensitivity of NPS was significantly higher than that of NW (74% vs. 49%, respectively; p < 0.01) and OPS (74% vs. 49%, respectively; p < 0.01).ConclusionsFlocked NPS collection may be the most effective alternative to NW and OPS for detection of respiratory viruses in adults with acute pharyngitis using TaqMan real-time polymerase chain reaction.
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