A New Infrared Atmospheric Sounding Interferometer Channel Selection and Assessment of Its Impact on Met Office NWP Forecasts

A new set of Infrared Atmospheric Sounding Interferometer(IASI) channels was re-selected from 314 EUMETSAT channels.In selecting channels,we calculated the impact of the individually added channel on the improvement in the analysis outputs from a one-dimensional variational analysis(1D-Var) for the Unified Model(UM) data assimilation system at the Met Office,using the channel score index(CSI) as a figure of merit.Then,200 channels were selected in order by counting each individual channel's CSI contribution.Compared with the operationally used 183 channels for the UM at the Met Office,the new set shares 149 channels,while the other 51 channels are new.Also examined is the selection from the entropy reduction method with the same 1D-Var approach.Results suggest that channel selection can be made in a more objective fashion using the proposed CSI method.This is because the most important channels can be selected across the whole IASI observation spectrum.In the experimental trial runs using the UM global assimilation system,the new channels had an overall neutral impact in terms of improvement in forecasts,as compared with results from the operational channels.However,upper-tropospheric moist biases shown in the control run with operational channels were significantly reduced in the experimental trial with the newly selected channels.The reduction of moist biases was mainly due to the additional water vapor channels,which are sensitive to the upper-tropospheric water vapor.     

The impact of cumulus parameterizations and microphysics schemes under different combinations on typhoon track prediction

This study examines the effects of cumulus parameterizations and microphysics schemes on the track forecast of typhoon Nabi using the Weather Research Forecast model. The study found that the effects of cumulus parameterizations on typhoon track forecast were comparatively strong and the typhoon track forecast of Kain-Fritsch (KF) was superior to that of Betts-Miller (BM). When KF was selected, the simulated results would be improved if microphysics schemes were selected than otherwise. The results from Ferrier, WSM6, and Lin were very close to those in the best track. KF performed well with the simulations of the western extension and eastern contraction changes of a North Pacific high as well as the distribution and strength of the typhoon wind field.     

A teleconnection pattern in upper-level meridional wind over the North African and Eurasian continent in summer

One-point correlation analysis on upper-level meridional wind identified the existence of a teleconnection pattern in July, which emerges from North Africa to East Asia along the westerly jet in the middle latitudes. We examined the spatial and temporal structures of this teleconnection pattern, and found the unique characteristics rather different from the patterns in other elements such as geopotential height, streamfunction and vorticity. We also investigated the relationship between this teleconnection and precipitation, and suggested that the teleconnection is a possible linkage of the EASM to the Indian monsoon, and even to subtropical heating anomalies over Atlantic.     

朝鲜半岛西北部古元古代高温变质-深熔作用:宏观和微观岩石学以及锆石U-Pb年代学制约

朝鲜半岛左接中国大陆右连日本岛链,其地质位置重要不言而喻,对其区域地质演化历史和构造属性的准确厘定,直接关系到对整个东北亚地质的全面理解和认识。本文对朝鲜半岛狼林地块西部的南浦群和甄山群的相关岩石进行了研究。野外露头、手标本和岩相学观察表明,南浦群和甄山群岩石保存了深熔作用的宏观和微观证据,矿物组合以及矿物间的反应结构表明南浦群和甄山群混合岩经历了角闪岩相到麻粒岩相的变质作用,并且在晚期熔体结晶过程中发生了逆反应或退变质过程。7件样品的锆石U-Pb定年结果显示,朝鲜半岛西北部地区在古元古代经历了多阶段(期)的变质和深熔作用过程。南浦群岩石在1917Ma可能经历了第一阶段(期)变质作用,在1877~1855Ma经历了第二阶段(期)变质深熔和石榴石持续生长,熔体冷却结晶时代为1842Ma。甄山群样品给出的变质深熔和石榴石生长的时代为1841~1830Ma,1785Ma可能代表深熔作用中抽取的熔体冷却的时代。但是,为何南浦群和甄山群样品记录的变质和深熔作用时代显示较大的差异,尚需更进一步的研究。综述前人研究成果可知,狼林地块与华北克拉通东部辽吉活动带,在变质和深熔作用类型方面存在不同之处,然而它们所记录的古元古代高温变质-深熔时代的一致性,表明二者可能至少在古元古代之前就形成了统一的大陆。     

Two Types of Diurnal Variations in Heavy Rainfall during July over Korea※

This study examined the characteristics of the diurnal variations of heavy rainfall (≥110 mm in 12 hours) in Korea and the related atmospheric circulation for July from 1980?2020. During the analysis period, two dominant pattens of diurnal variation of the heavy rainfall emerged: all-day heavy rainfall (AD) and morning only heavy rainfall (MO) types. For the AD-type, the heavy rainfall is caused by abundant moisture content in conjunction with active convection in the morning (0000?1200, LST; LST = UTC + 9) and the afternoon hours (1200?2400 LST). These systems are related to the enhanced moisture inflow and upward motion induced by the strengthening of the western North Pacific subtropical high and upper-tropospheric jet. For the MO-type, heavy rainfall occurs mostly in the morning hours; the associated atmospheric patterns are similar to the climatology. We find that the atmospheric pattern related to severe heavy rainfalls in 2020 corresponds to a typical AD-type and resembles the 1991 heavy-rainfall system in its overall synoptic/mesoscale circulations. The present results imply that extremely heavy rainfall episodes in Korea during the 2020 summer may occur again in the future associated with the recurring atmospheric phenomenon related to the heavy rainfall.     

Dietary intake of bamboo vinegar and charcoal powder (BVC) enhances resistance of African catfish Clarias gariepinus to bacterial pathogen

Although the immunomodulatory activity of bamboo vinegar and charcoal powder (BVC) has been increasingly documented in domestic animals, the use of BVC as immun...     

Precambrian crustal evolution in Rangrim Massif,Korean Peninsula

Petrological, chronological and geotectonic geological analysis of Precambrian metamorphic rock in Korean Peninsula shows that the remnants （ 〉3.4 Ga） of continental nuclei crust were formed in the Paleoarchean in the Rangrim Massif. In the massif, the main formation ages of continental crust range from 3.2 Ga to 2.5 Ga, its important growing period was 2.8 - 2. 5 Ga. The subsequent expansion period of the Rangrim Massif was 2. 4 - 2. 2 Ga. The division events occurred in 1.85 Ga and in the Late Paleoproterozoic-Early Mesoproterozoic, respectively. Since then the massif was relatively stable. However, the last division of the Rangrim Massif occurred at 793 Ma.