Climate prediction of the seasonal sea-ice early melt onset in the Bering Sea

基于大尺度环流异常对海冰消融的影响过程,本文采用年际增量预测方法研制了白令海季节性海冰早期消融开始日期(EMO)的统计预测模型.预测模型选取了3个具有明确物理意义的预测因子:1月波弗特高压,前期11月东西伯利亚地区海平面气压,以及11月东欧平原积雪覆盖率。1月波弗特高压可以通过海气相互作用影响白令海地区海温异常,该海温异常能够从1月持续到3月,进而影响白令海EMO.11月东西伯利亚地区海平面气压与11月至次年2月北太平洋中纬度东部海温密切相关。伴随着北太平洋中纬度东部冷海温异常的出现,白令海地区会出现暖海温异常,进而导致白令海海冰范围减少,EMO较晚.1月北极偶极子异常是11月东欧平原积雪覆盖率影响次年白令海EMO的桥梁之一.1981-2022年的交叉检验结果表明:统计模型对白令海EMO具有较好的预测能力,预测与观测的EMO之间时间相关系数达到了0.45,超过了99%的置信水平.统计模型对白令海EMO正常年份和异常年份的预测准确率分别为60%和41%.

Seasonal variations in the onset of ulcerative colitis in Japan

AIM:To investigate seasonal variations in the onset and relapse of ulcerative colitis(UC)in Japanese patients.METHODS:Between 1994 and 2006,198 Japanese patients diagnosed with UC according to conventional criteria in an academic hospital were enrolled for onset evaluation.Among 265 Japanese patients with UC who were observed for more than 12 mo,165 patients relapsed(239 times)and were enrolled for relapse evaluation.The patients’symptoms were recorded each month for 12 consecutive years.RESULTS:There was monthly seasonality in symptom onset during October and March for UC.The onset of symptoms in UC patients frequently occurred during the winter.Variation in UC onset was observed according to both month(P=0.015)and season(P=0.048).Relapse commonly occurred in October,and variations in relapse were not significant either in month(P=0.52)or season(P=0.12).Upper respiratory inflammation was the main factor responsible for relapse.CONCLUSION:Our results suggest that environmental factors associated with winter and spring seasonality may be responsible for triggering the clinical onset of UC in Japan.

CHARACTERISTICS OF MIDDLE EAST JET STREAM DURING SEASONAL TRANSITION AND ITS RELATION WITH INDIAN SUMMER MONSOON ONSET

By using the NCEP/NCAR pentad reanalysis data from 1968 to 2009, the variation characteristics of Middle East jet stream(MEJS) and its thermal mechanism during seasonal transition are studied. Results show that the intensity and south-north location of MEJS center exhibit obvious seasonal variation characteristics. When MEJS is strong, it is at 27.5°N from the 67 th pentad to the 24 th pentad the following year; when MEJS is weak, it is at 45°N from the 38 th pentad to the 44 th pentad. The first Empirical Orthogonal Function(EOF) mode of 200-hPa zonal wind field shows that MEJS is mainly over Egypt and Saudi Arabia in winter and over the eastern Black Sea and the eastern Aral Sea in summer. MEJS intensity markedly weakens in summer in comparison with that in winter. The 26th-31 st pentad is the spring-summer transition of MEJS, and the 54th-61 st pentad the autumn-winter transition. During the two seasonal transitions, the temporal variations of the 500-200 hPa south-north temperature difference(SNTD) well match with 200-hPa zonal wind velocity, indicating that the former leads to the latter following the principle of thermal wind. A case analysis shows that there is a close relation between the onset date of Indian summer monsoon and the transition date of MEJS seasonal transition. When the outbreak date of Indian summer monsoon is earlier than normal, MEJS moves northward earlier because the larger SNTD between 500-200 hPa moves northward earlier, with the westerly jet in the lower troposphere over 40°-90°E appearing earlier than normal, and vice versa.

Interannual Variation of the Onset of Yunnan’s Rainy Season and Its Relationships with the Arctic Oscillation of the Preceding Winter

Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timing of the rainy sea-son by using the NCEP/NCAR reanalysis and observational precipitation data for 1961-2010. The results indicated that, on an interannual time scale, intense Asian summer monsoon and an active EU-pattern wave train circulation in its positive phase, associated with a cold cyclonic cell covering the western part of the East Asian subtropical westerly jet (EASWJ), jointly contributed to the onset of the rainy season in May. Otherwise, the onset might be suppressed. The cold cyclonic cell over East Asia likely led to the southward shift and enhancement of EASWJ as well as its secondary circulation around the jet entrance, which could provide a favorable dynamic and thermal condition for rainfalls in Yunnan as was revealed in previous studies on 10 - 30-day time scale. Further examination showed that the preceding wintertime AO played a significant role in the timing of the onset of the rainy season before the mid-1980s’ by mostly modulating the wave-train-like circulation over East Asia in May. During that time period, when the AO index of the previous winter was positive (negative), Yunnan’s rainy season tended to begin earlier (later) than normal. Correspond-ingly, the precipitation in May was also closely linked to wintertime AO.

Comparison of Rainy Season Onset, Cessation and Duration for Ghana from RegCM4 and GMet Datasets

The socio-economic sector of West African countries is rain-fed agriculture driven. Information regarding the onset, cessation and duration of the rainy season is thus, very essential. In this paper, a comparison of the onset, cessation and duration of the rainy season has been carried out using simulated rainfall data from the fourth generation Regional Climate Model (RegCM4) and rain gauge measurements from Ghana Meteorological Agency (GMet), covering a period of 1998 to 2012. Similar onset and cessation dates were seen in both the simulated and guage rainfall measurements for the various agro-ecological zones, resulting in similar duration of the rainy season. The average duration of the rainy season were less than 200 days for the savannah and coastal zones whereas the duration of the rainy season were beyond 200 days for the forest and transition zones. The bias of these comparisons was less than 30 days and the root mean square error (RMSE) values were less than 15 days for all stations, except Saltpond. The Pearson’s correlation (r) typically ranged between 0.4 and 0.8. However, negative correlations were observed for Tamale in the savannah zone, and the entire coastal zone. These findings are indications that RegCM4 has the potential to clearly simulate the movement of the rain belt, and thus, could fairly determine the onset, cessation and duration of the rainy season. The findings have significant contributions to effective water resource management and food security in Ghana, as the thriving of these sectors depend on the dynamics of the rainfall seasons.

SEASONAL AND INTER-ANNUAL VARIABILITY OF THE SOUTH CHINA SEA WARM POOL AND ITS RELATION TO THE SOUTH CHINA SEA MONSOON ONSET

The South China Sea warm pool interacts vigorously with the summer monsoon which is active in the region. However, there has not been a definition concerning the former warm pool which is as specific as that for the latter. The seasonal and inter-annual variability of the South China Sea warm pool and its relations to the South China Sea monsoon onset were analyzed using Levitus and NCEP/NCAR OISST data. The results show that, the seasonal variability of the South China Sea warm pool is obvious, which is weak in winter, develops rapidly in spring, becomes strong and extensive in summer and early autumn, and quickly decays from mid-autumn. The South China Sea warm pool is 55 m in thickness in the strongest period and its axis is oriented from southwest to northeast with the main section locating along the western offshore steep slope of northern Kalimantan-Palawan Island. For the warm pools in the South China Sea, west Pacific and Indian Ocean, the oscillation, which is within the same large scale air-sea coupling system, is periodic around 5 years. There are additional oscillations of about 2.5 years and simultaneous inter-annual variations for the latter two warm pools. The intensity of the South China Sea warm pool varies by a lag of about 5 months as compared to the west Pacific one. The result also indicates that the inter-annual variation of the intensity index is closely related with the onset time of the South China Sea monsoon. When the former is persistently warmer (colder) in preceding winter and spring, the monsoon in the South China Sea usually sets in on a later (earlier) date in early summer. The relation is associated with the activity of the high pressure over the sea in early summer. An oceanic background is given for the prediction of the South China Sea summer monsoon, though the mechanism through which the warm pool and eventually the monsoon are affected remains unclear.

强直性脊柱炎发病与二十四节气相关性研究

目的:分析陕西地区近19年强直性脊柱炎发病与二十四节气间的相关性,从时间医学角度为因时制宜理论提供临床依据。方法:采用回顾性研究方法对西安市第五医院2002年2月4日至2020年2月3日收治的12645例强直性脊柱炎住院患者的病历资料进行分析,应用圆形统计分析确定其发病高峰节气及相对高峰期。结果:2002-2020年陕西地区强直性脊柱炎患者的在发病节气上具有集中趋势(Z=47.73,P<0.05),大暑(8月5日)是发病的高峰节气,相对高峰期为春分到大雪(3月21日至12月20日)。结论:强直性脊柱炎虽不是季节性流行病,但是其发病与气候、环境及二十四节气的变化有一定的影响,陕西地区强直性脊柱炎的发病节气具有一定的集中趋势,大暑前后是发病高峰期,提示应注意该节气期间疾病的预防和早期治疗。

发热儿童的高热惊厥发生现状及其高危因素分析

目的探讨发热儿童的高热惊厥发生现状及其高危因素。方法方便选取2021年1月—2023年2月就诊于广东省东莞市长安医院发热门诊的2995例发热患儿为研究对象,经查阅患儿电子病历档案或询问患儿家长收集资料,调查发热儿童的高热惊厥发生现状,并分析其发生的相关危险因素。结果2995例发热患儿中,发生高热惊厥120例(4.01%),未发生高热惊厥2875例(95.99%)。单因素分析显示,高热惊厥组年龄<3岁、性别男、初发温度≥39.1℃、7~9月发病比例较非高热惊厥组高,差异有统计学意义(P均<0.05)。两组癫痫家族史、高热惊厥家族史、原发性感染性疾病、出生方式、围产期缺氧史和平均红细胞血红蛋白、平均红细胞体积、血红蛋白对比,差异无统计学意义(P均>0.05);经Logistic回归分析显示,年龄(OR=20.080,95%CI:12.524~32.192)、性别(OR=1.796,95%CI:1.195~2.700)、初发温度(OR=6.976,95%CI:4.793~10.153)、发病季节(OR=2.046,95%CI:1.250~3.349)是发热儿童高热惊厥发生的高危因素,差异有统计学意义(P均<0.05)。结论发热儿童高热惊厥发生率较高,其发生与患儿年龄、性别、发病季节和初发温度密切相关,应结合上述危险因素制定预防措施,以降低高热惊厥发生率。

2023年华南开汛偏早与大气环流和海温的关系

采用合成、相关分析及相关物理量诊断等方法,分析了华南地区三重La Ni1a背景下2023年华南开汛偏早的大气环流和海温特征并与2022年作对比,结果表明:(1)2022和2023年3月广东降水偏多与前冬北太平洋暖海温相关,2022、2023年华南开汛偏早分别与前冬中印度洋海岭海域海温、前冬东太平洋海丘的以东海域海温增暖有关。(2)2022和2023年3月850 hPa风场华南沿海均呈现反气旋式分布,华南处于西南到偏南气流中有利水汽输送。两年开汛偏早与冷空气南下有关。(3)2022和2023年3月华南地区局地哈德莱环流在赤道附近北支上升气流加强,北支下沉支减弱且南退,在0°N—20°N范围内为负距平,有利于2022和2023年3月广东降水偏多。

Seasonal Transition of Summer Rainy Season over Indochina and Adjacent Monsoon Region

The mean onset and withdrawal of summer rainy season over the Indochina Peninsula were investigated using 5-day averaged rainfall data (1975-87). The mean seasonal transition process during onset and retreat phases in Indochina, India and the South China Sea is also examined using 5-day mean OLR (1975-87) and 850 hPa wind (1980-88) data. It was found that the onset of summer rainy season begins earlier in the inland region of Indochina (Thailand) in late April to early May than in the coastal region along the Bay of Bengal. This early onset of rainy season is due to pre-monsoon rain under the mid-latitude westerly wind regime. The full summer monsoon circulation begins to establish in mid-May, causing active convective activity both over the west coast of Indochina and the central South China Sea. In case of withdrawal, the earliest retreat of summer rainy season is found in the central northern part of Indochina in late September. The wind field, on the other hand, already changes to easterlies in the northern South China Sea in early September. This easterly wind system covers the eastern part of Indochina where post-monsoon rain is still active. In late October, the wind field turns to winter time situation, but post monsoon rain still continues in the southern part of the Indochina Peninsula until late November.

Atmospheric Circulation Characteristics Associated with the Onset of Asian Summer Monsoon

The onset of the Asian summer monsoon has been a focus in the monsoon study for many years. In this paper, we study the variability and predictability of the Asian summer monsoon onset and demonstrate that this onset is associated with specific atmospheric circulation characteristics. The outbreak of the Asian summer mol）~soon is found to occur first over the southwestern part of the South China Sea （SCS） and the Malay Peninsula region, and the monsoon onset is closely related to intra-seasonal oscillations in the lower atmosphere. These intra-seasonal oscillations consist of two low-frequency vortex pairs, one located to the east of the Philippines and the other over the tropical eastern Indian Ocean. Prior to the Asian summer monsoon onset, a strong low-frequency westerly emerges over the equatorial Indian Ocean and the low-frequency vortex pair develops symmetrically along the equator. The formation and evolution of these low-frequency vortices are important and serve as a good indicator for the Asian summer monsoon onset. The relationship between the northward jumps of the westerly jet over East Asia and the Asian summer monsoon onset over SCS is investigated. It is shown that the northward jump of the westerly jet occurs twice during the transition from winter to summer and these jumps are closely related to the summer monsoon development. The first northward jump （from 25°-28°N to around 30°N） occurs on 8 May on average, about 7 days ahead of the summer monsoon onset over the SCS. It is found that the reverse of meridional temperature gradient in the upper-middle troposphere （500-200 hPa） and the enhancement and northward movement of the subtropical jet in the Southern Hemispheric subtropics are responsible for the first northward jump of the westerly jet.

The Onset of the Monsoon over the Bay of Bengal:The Observed Common Features for 2008-2011

In situ buoy observation data spanning four years(2008-2011) were collected and used to perform a composite analysis of the monsoon onset process in the Bay of Bengal(BoB).The sea surface temperature(SST) in the central BoB increases dramatically during the monsoon transition period and reaches its annual maximum just before the onset of the monsoon.This process is illustrated by the northward-propagating deep convection phase of the intraseasonal oscillation and the establishment of a steady southwest wind.It is argued that the SST peak plays a potential role in triggering the onset of the monsoon in the BoB and its vicinity.The general picture of the BoB monsoon onset summarized here reveals the possibility of regional land-ocean-atmosphere interaction.This possibility deserves further examination.

THE RELATIONSHIP BETWEEN SOUTH CHINA SEA SOUTHWEST MONSOON ANOMALIES AND IMPORTANT WEATHER IN GUANGDONG PROVINCE DURING THE RAINING SEASONS

The activity of South China Sea southwest monsoon (SCSSM) has direct impacts on the anomalies of important weather in Guangdong province during the raining seasons. So it is necessary to explore thoroughly the activity pattern of SCSSM and its relationship with important weather anomalies in the province. In this paper, the methods of composite analysis and correlation statistics are used to study the relationship between the onset date and intensity of SCSSM and the important weather, such as precipitation trends in Guangdong province during the annually first and second raining seasons, the timing of the annually first and last typhoon and the number of typhoons landing in Guangdong province. The results show that the rainfall is less than normal during the first raining season, but more than normal during the second one and there are more tropical cyclones landing in Guangdong province in the years of early SCSSM onset. The rainfall is more than normal during the second raining season and there are more tropical cyclones landing in Guangdong province in the years of strong SCSSM. The relationship between the SST of April - June, July - September and previous winter (December - February) and 500 hPa geopotential height and the onset date and intensity of SCSSM is analyzed. Some mechanisms between the onset dates and intensity of SCSSM and the important weather anomalies in Guangdong province are preliminarily explored. The results can be used for reference in short-term climate forecast.

Low-Frequency Vortex Pair over the Tropical Eastern Indian Ocean and the South China Sea Summer Monsoon Onset

In this paper,the relationship between a pair of low-frequency vortexes over the equatorial Indian Ocean and the South China Sea(SCS) summer monsoon onset is studied based on a multi-year(1980-2003) analysis.A pair of vortexes symmetric about the equator is an important feature prior to the SCS summer monsoon onset.A composite analysis shows that the life cycle of the pair of vortexes is closely associated with the SCS summer monsoon onset.The westerly between the twin cyclones is an important factor to the SCS summer monsoon onset process.

2019—2021年咸阳市某民族高校学生肺结核发病分析

目的分析咸阳市某民族高校学生2019—2021年肺结核发病情况,为提高学校和肺结核高发地区防控水平提供数据支持。方法回顾性研究咸阳市某民族高校学生系统,以2019年1月—2021年12月在校学生作为研究对象,基于学校学生系统,采集学生性别、年级、民族、地区等一般信息,并提取肺结核患病学生的一般信息及月份发病情况。采用描述性方法分析2019—2021年咸阳市某民族高校学生肺结核发病情况,采用SPSS 23.0统计学软件分析2019—2021年咸阳市某民族高校学生发病时间分布及发病人群特征分布特征(包括性别、年级、地区)。结果2019—2021年咸阳市某民族高校学生累计报告肺结核患者为255例,发病率为668.20/10万,其中2019年、2020年、2021年发病率分别925.53/10万、540.58/10万、571.34/10万,2019年发病率最高。2019—2021年咸阳市某民族高校学生各月均有肺结核病例报告,其中2019年报告高峰为3、9、12月,2020—2021年病例报告曲线变化显示基本一致,3—4月为肺结核报告高峰,接下来月份均处于缓慢下降,9—10月为小高峰;来自西藏地区不同市大学生2019—2022年肺结核发病情况不同,差异有统计学意义(P<0.05);按照年份来看,不同性别、年级和生源居住地的大学生肺结核发病情况不同,差异有统计学意义(P<0.001)。结论咸阳市某民族高校学生2019—2021年肺结核发病率呈不规律波动,但总体发病率仍然较高;发病高峰时间主要集中于3—4月、9—10月;低年级、男性学生应为结核病防控主要人群;藏区结核病患病率波动较大,可能与地区医疗水平提高有关,而低医疗水平地区仍然为重点防治地区。针对高风险重点人群,应加强结核病筛查及防控管理,预防结核病流行与蔓延。

气候变暖背景下青海三江源区季节冻土冻融特征研究

青海三江源区是全球气候变化的敏感区和生态环境脆弱区,目前正面临着冻土退化的问题。本研究基于三江源区18个国家气象站1961—2021年气象观测资料,对气候变暖前后季节冻土冻融特征进行对比分析。结果表明:三江源区年平均气温为-0.34℃,呈东高西低分布,总体以0.38℃·(10a)^(-1)的速率上升,并在1997年发生突变,突变后气温显著升高。平均年最大季节冻结深度为142.5 cm,自西北向东南减小,总体以2.4 cm·(10a)^(-1)速率退化,与变暖前相比减少了11 cm。平均地表冻结初日为10月24日,以1.0 d·(10a)^(-1)速率推迟,平均地表冻结终日为5月18日,以3.3 d·(10a)^(-1)速率提前,与变暖前相比,地表冻结终日提前了12 d,地表冻结初日推迟了14 d。季节冻土平均冻结时间为133.9 d,呈西高东低分布,总体以1.9 d·(10a)^(-1)速率减少,与变暖前相比减少了8.8 d。年最大冻结深度及冻结时间分别在2004年和2002年发生突变,相比气温均有一定滞后。这说明,季节冻土在受气温变化影响同时,还受地形、人类活动等其他因素影响。该研究揭示了三江源区季节冻土冻结作用弱化的现象,研究成果可为应对气候变化、工程建设等提供参考。

亚洲季风降水季节演变特征的气候系统模式模拟:基于FGOALS-g3和FGOALS-g2的比较评估

亚洲季风降水的季节演变对亚洲农业生产和社会经济有重要的影响。本文通过与观测资料对比,评估了中国科学院大气物理研究所研发的最新版本的气候系统模式FGOALS-g3相对于上一版本FGOALS-g2对亚洲季风降水季节演变的模拟能力,并通过与FGOALS-g3海温驱动的大气模式结果对比,研究海气相互作用对季风降水量年循环模拟的影响。结果表明,FGOALS-g3提高了对南亚和西北太平洋降水量年循环的模拟能力,部分源于大气模式的改进,但对其他区域模拟性能改进不明显。FGOALS-g3对西北太平洋季风爆发、撤退、峰值和持续时间、阿拉伯海东部季风撤退和持续时间以及印度半岛至中国南海季风峰值时间的模拟偏差有所改进,且考虑模式自身海气耦合过程后,可显著改善西北太平洋区域降水量年循环等模拟偏差。与FGOALS-g2相比,在南亚和中南半岛区域,FGOALS-g3模拟的季风爆发更晚,这是由非洲大陆降水量干偏差导致索马里越赤道急流减弱,加剧该区域5月负降水量偏差导致。在西北太平洋,FGOALS-g3显著改善了季风爆发西侧推迟而东侧提前的模拟偏差,原因是太平洋东暖西冷的海温偏差显著减小,局地Hadley环流增强,在该区域产生异常下沉运动,减小了西侧1月降水量湿偏差,使5月相对于1月的降水量增加,而东侧5月降水量与1月降水量的干偏差得以互相抵消。研究表明热带大尺度海温型模拟偏差的改进对提高亚洲季风降水量年循环的模拟能力有重要作用。

2022年广东开汛偏早成因浅析

基于广东1961—2022年气象站的逐日降水资料、NCEP/NCAR 2.5°×2.5°全球再分析资料及哈德里中心1°×1°全球海表面温度(HadISST)资料,通过定义关键海区指数,分析影响2022年广东开汛异常偏早的海温因子,结果表明:2022年广东开汛时经、纬向风均呈现强的正异常中心,且为3月以来首次经、纬向风正值中心重叠。广东开汛偏早年,前期热带印度洋、海洋性大陆西部海域及黑潮区海域偏暖,赤道中东太平洋偏暖而西太暖池中部偏冷;反之亦然。2022年引起广东开汛偏早的主导先兆因子可能为热带南印度洋的马斯克林群岛海域及海洋性大陆西海域偏暖信号,而非ENSO信号。

青藏高原冬季积雪与华南前汛期降水年际变率的联系

利用1979—2018年青藏高原(简称高原,下同)卫星积雪数据集、华南地区261站逐日降水及ERA5再分析资料,探讨了高原冬季积雪与华南前汛期降水的联系。结果表明:1)高原西部积雪与华南前汛期降水的正相关关系最为稳定,其主要影响前汛期的锋面降水,对夏季风降水的影响较小;2)华南前汛期在高原西部积雪偏多年比偏少年偏早20 d,使得前汛期降雨日数偏多,持续时间偏长,总降水量偏多,而降水强度受积雪的影响较小;3)高原积雪偏多年,积雪的冷却作用形成了低层异常反气旋环流,而东亚沿岸为“+-+”的位势高度异常,中纬度“西高东低”的环流配置有利于中高纬冷空气南侵,使得华南上空温度偏低,同时偏强偏南的西太平洋副热带高压加强了低纬地区偏南气流和水汽输送。3—4月锋面在华南北部南北摆动,4月初偏北干冷空气南侵和偏南暖湿气流的持续北推使得锋面加强,触发了前汛期的较早建立;积雪偏少年冷空气和偏南暖湿气流均较弱,华南北部锋面在4月初中断,4月中下旬华南北部锋面在偏北弱冷空气和偏南暖湿气流的共同作用下重新建立,从而华南前汛期开始偏晚。

论山西地区外感肺系疾病的防治

外感肺系疾病为临床常见多发疾病,探讨对外感肺系疾病的预防与治疗具有重要意义。从中医三因制宜、未病先防等理论出发,依据外感肺系疾病特点,结合中医经典古籍对外感肺系疾病的论述和山西冬季长而寒冷干燥,春季温差大、寒燥多风的气候特点,认为山西易感人群多为太阳藩篱不固、少阳相火易动体质。本着遵循“正气存内,邪不可干,避其毒气”原则,认为山西地区防治外感肺系疾病当从太阳、少阳两经和补充阴液入手,体虚者则需培补正气,确立和解养阴法与补气养阴法为山西地区防治外感肺系疾病的主要治则,推荐处方为柴桂沙麦汤、参芪扶正汤。