Madden-Julian Oscillation: Its Discovery,Dynamics, and Impact on East Asia   总被引：1，自引：0，他引：1  

Tim Li  Jian Ling  Pang-Chi Hsu 《Acta Meteorologica Sinica》2020,34(1):20-42

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A time‐split, forward‐backward numerical model for solving a nonhydrostatic and compressible system of equations     

WU&#;RON HSU  WEN&#;YIH SUN 《地球，A辑:动力气象学与海洋学》2001,53(3):279-299

In this paper, we present a numerical procedure for solving a 2‐dimensional, compressible, and nonhydrostatic system of equations. A forward‐backward integration scheme is applied to treat high‐frequency and internal gravity waves explicitly. The numerical procedure is shown to be neutral in time as long as a Courant–Friedrichs–Lewy criterion is met. Compared to the leap‐frog‐scheme most models use, this method involves only two time steps, which requires less memory and is also free from unstable computational modes. Hence, a time‐filter is not needed. Advection and diffusion terms are calculated with a time step longer than sound‐wave related terms, so that extensive computer time can be saved. In addition, a new numerical procedure for the free‐slip bottom boundary condition is developed to avoid using inaccurate one‐sided finite difference of pressure in the surface horizontal momentum equation when the terrain effect is considered. We have demonstrated the accuracy and stability of this new model in both linear and nonlinear situations. In linear mountain wave simulations, the model results match the corresponding analytical solution very closely for all three cases presented in this paper. The analytical streamlines for uniform flow over a narrow mountain range were obtained through numerical integration of Queney's mathematical solution. It was found Queney's original diagram is not very accurate. The diagram had to be redrawn before it was used to verify our model results. For nonlinear tests, we simulated the famous 1972 Boulder windstorm and a bubble convection in an isentropic enviroment. Although there are no analytical solutions for the two nonlinear tests, the model results are shown to be very robust in terms of spatial resolution, lateral boundary conditions, and the use of the time-split scheme.  相似文献   

Application of vector autoregressive time series analysis to aerosol studies   总被引：1，自引：0，他引：1  

KUANG-JUNG HSU 《Tellus. Series B, Chemical and physical meteorology》1997,49(3):327-342

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An Interesting Anisic Fauna of Machangping, Pingyueh, Kueichou     

TE-You Hsu  T. C. TSENC 《地质学报》1942,(Z2):207-211

正 As the Middle Triassic of China is generally fossiliferous only in its upper part, i. e., the Ladinic, the discovery of the Anisic fauna is interesting and it seems desirable to give an account of the remains. The material was collected  相似文献   

Revision of the Chingyen Triassic Fauna from Kueichou     

TE-YOU HSU  K. CHEN Geological Survey of China 《地质学报》1943,(Z2):130-139

正 INTRODUCTION About half a century ago, P. Fuchs collected a rich Triassic fauna from Sitzishan, Tsin-ngai, Kueichou. This was studied by E. Koken~1 who described the following species: Worthenia tuberculifera (I)~a, W. nuda (2), Pleurotomaria  相似文献   

Contribution to the Marine Lower Triassic Fauna of Southern China     

TE-YOU HSU 《地质学报》1937,(Z1)

Early in 1936 Dr. T. K. Huang, Messrs. S. F. Sheng, I. Ting andK. S. Tsui during their field work in the Changhsing coal field, NWChekiang, found Scythic pelecypods and ammonoids in the so-calledChinglung limestone of that region. The discovery of Lower Triassic  相似文献   

Influence of the Boreal Summer Intraseasonal Oscillation on Extreme Temperature Events in the Northern Hemisphere     

Yifei Diao  Tim Li  Pang-Chi Hsu 《Acta Meteorologica Sinica》2018,32(4):534-547

The impact of the boreal summer intraseasonal oscillation (BSISO) on extreme hot and cool events was investigated, by analyzing the observed and reanalysis data for the period from 1983 to 2012. It is found that the frequency of the extreme events in middle and high latitudes is significantly modulated by the BSISO convection in the tropics, with a 3–9-day lag. During phases 1 and 2 when the BSISO positive rainfall anomaly is primarily located over a northwest–southeast oriented belt extending from India to Maritime Continent and a negative rainfall anomaly appears in western North Pacific, the frequency of extreme hot events is 40% more than the frequency of non-extreme hot events. Most noticeable increase appears in midlatitude North Pacific (north of 40°N) and higher-latitude polar region.Two physical mechanisms are primarily responsible for the change of the extreme frequency. First, an upper-tropospheric Rossby wave train (due to the wave energy propagation) is generated in response to a negative heating anomaly over tropical western North Pacific in phases 1 and 2. This wave train consists of a strong high pressure anomaly center northeast of Japan, a weak low pressure anomaly center over Alaska, and a strong high pressure anomaly center over the western coast of United States. Easterly anomalies to the south of the two strong midlatitude high pressure centers weaken the climatological subtropical jet along 40°N, which is accompanied by anomalous subsidence and warming in North Pacific north of 40°N. Second, an enhanced monsoonal heating over South Asia and East Asia sets up a transverse monsoonal overturning circulation, with large-scale ascending (descending) anomalies over tropical Indian (Pacific) Ocean. Both the processes favor more frequent extreme hot events in higher-latitude Northern Hemisphere. An anomalous atmospheric general circulation model is used to confirm the tropical heating effect.  相似文献   

利用重力卫星GRACE监测亚马逊流域2002-2010年的陆地水变化   总被引：2，自引：0，他引：2       下载免费PDF全文

冯伟  Jean-Michel LEMOINE  钟敏  许厚泽 《地球物理学报》2012,55(3):814-821

本文利用GRACE (Gravity Recovery and Climate Experiment) 卫星重力资料研究了亚马逊流域2002-2010年的陆地水变化,并与水文模式和降雨资料进行了比较分析.在年际尺度上,GRACE结果表明:2002-2003年和2005年,亚马逊流域发生明显的干旱现象;2007年至2009年,陆地水呈逐年增加的趋势,并在2009年6月变化值达到最大,为772±181 km³;自2009年6月至2010年12月,陆地水总量又急剧减少了1139±262 km³,这相当于全球海平面上升3.2±0.7 mm所需的水量.水文模式得到的亚马逊流域陆地水在2010年也表现出明显的减少.降雨资料与GRACE观测资料有很好的一致性.在2005年和2010年的干旱期,亚马逊流域的降雨显著减少,说明降雨是亚马逊流域陆地水变化的重要因素.此外,本文采用的尺度因子的方法有效地降低了GRACE后处理误差的影响.  相似文献   

Dimension and frequency of bar formation in a braided river     

Hsuan-pei AN  Su-chin CHEN  Hsun-chuan CHAN  Yi HSU 《国际泥沙研究》2013,28(3):358-367

This paper presents flume and field observations of a bank-confined braided river. Morphological features, including plan form configuration, channel width, and main channel migration, were examined by a series of experiments. Repeated measurements of channel morphology, provided a basis to estimate the relationship between noncumulative frequency of bars and bar area. Additional results from the Dajia River, located in Central Western Taiwan, were presented to provide a reference data set for comparing the laboratory and field data. The results indicate that the relationship between bar length and width can be predicted by a simple best-fit power function relating to self-similarity characteristics. The Hurst index by Walsh and Hicks (2002) provides acceptable predictions of the bar length and width observed in the experiments and confirmed by the field investigations. Eexperimental and field results both show that large river width yields a uniform distribution of bar areas with the similar discharge, leading to a large value of exponent (β) in the model. The river width is confirmed to be a critical parameter in the main channel shift. A small increase in channel width likely increased rapidly the shift cycle.  相似文献   

基于统计检验法研究Amurian板块相对独立性   总被引：1，自引：0，他引：1       下载免费PDF全文

郭东美  许厚泽 《地球物理学报》2013,56(4):1246-1252

Amurian 板块是Zonenshain等提出的提出的东北亚地区内部一个构造亚板块.Amurian板块自提出以来就一直受到地学界的广泛重视.它到底是欧亚大陆的一部分,还是独立于欧亚大陆之外的一个独立次级构造块体?这个问题一直是是东亚,乃至欧亚大陆构造动力学研究的核心问题之一.许多学者从地质和地球物理学两个角度研究了Amurian板块存在的可能性.但是复杂的构造特征和稀少且弥散的地震分布使得Amurian问题充满了争议.全球卫星定位系统(GPS)技术的不断进步使得在短时间获得高精度、大范围、准实时的地壳运动观测数据,并确定地壳运动速度场成为可能.本文利用东北亚地区最新GPS资料,从大地测量学角度对东北亚地区的地壳运动特征进行分析,基于统计检验方法重点研究Amurian板块相对欧亚大陆的独立性及其边界等问题.  相似文献