QINGHAI-XIZANG SURFACE LONG-WAVE RADIATION PARAMETERIZATION WITH ITS CLIMATIC CALCULATION^*     

Gao Ge  Zhang Lanying  Weng Duming 《Acta Meteorologica Sinica》1998,12(2):190-198

In the context of August 1982- July 1983 radiation balance data of the Qinghai-Xizang Plateau, detailed study is made of the relation between the active-surface temperature and surface temperature, proposing two parameterization schemes on surface long-wave radiation(SLWR)of the form U=kδσ(T₀+273)⁴ and U=δσ[(T₀+273)⁴+△T)]⁴, where k and △T are indicated by parameterization equations, separately, others being in conventional notation. Retrieved verification shows the two formulae to be of the same fitting accuracy with the mean relative error of 3.6% and suitable for computing instantaneous and mean flux density, alongside analyzed daily and annual variations of k and △T. Eventually. SLWR in the target area is investigated and its climatic characteristics examined.  相似文献   

Detection and Correction of AMSR-E Radio-Frequency Interference   总被引：2，自引：0，他引：2       下载免费PDF全文

WU Ying  WENG Fuzhong 《Acta Meteorologica Sinica》2011,25(5):669-681

Radio-frequency interference (RFI) affects greatly the quality of the data and retrieval products from space-borne microwave radiometry. Analysis of the Advanced Microwave Scanning Radiometer on the Earth Observing System (AMSR-E) Aqua satellite observations reveals very strong and widespread RFI contam- inations on the C- and X-band data. Fortunately, the strong and moderate RFI signals can be easily identified using an index on observed brightness temperature spectrum. It is the weak RFI that is diffi- cult to be separated from the nature surface emission. In this study, a new algorithm is proposed for RFI detection and correction. The simulated brightness temperature is used as a background signal (B) and a departure of the observation from the background (O-B) is utilized for detection of RFI. It is found that the O-B departure can result from either a natural event (e.g., precipitation or flooding) or an RFI signal. A separation between the nature event and RFI is further realized based on the scattering index (SI). A positive SI index and low brightness temperatures at high frequencies indicate precipitation. In the RFI correction, a relationship between AMSR-E measurements at 10.65 GHz and those at 18.7 or 6.925 GHz is first developed using the AMSR-E training data sets under RFI-free conditions. Contamination of AMSR-E measurements at 10.65 GHz is then predicted from the RFI-free measurements at 18.7 or 6.925 GHz using this relationship. It is shown that AMSR-E measurements with the RFI-correction algorithm have better agreement with simulations in a variety of surface conditions.  相似文献   

Iron and phosphorus effects on the growth of Cryptomonas sp. (Cryptophyceae) and their availability in sediments from the Pearl River Estuary, China   总被引：2，自引：0，他引：2  

Huan-Xin Weng  Ya-Chao Qin  Xiang-Wei Sun  Hailiang Dong  Xiang-Hua Chen 《Estuarine, Coastal and Shelf Science》2007,73(3-4):501-509

Based on lab-culture experiments analyzing limitation and combination of iron and phosphorus on the growth of Cryptomonas sp. (Cryptophyceae), and the study of accumulation and release of Fe-bound P in sediment cores collected from the marine region of the Pearl River Estuary, China, reasons for the high frequency of phytoplankton bloom therein are discussed. Results show that the combined effect of Fe and P can obviously accelerate algal development, and the optimum culture conditions maintaining maximum growth rate are 0.05 μM Fe and 50 μM P. Cellular contents of Fe and P is consistent and the P:Fe molar ratio is 159:1. The optimum range of the P:Fe molar ratio in culture experiments for cell incubation is 500–1400. The vertical trends of total Fe and total P variations in sediments are parallel. Fe-bound P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34–80% of exchangeable P and 4–23% of exchangeable Fe are concurrently released from the surficial sediments. This is a possible way by which nutrients are made available to phytoplankton. These factors might be responsible for a high frequency of harmful algal blooms in the Pearl River Estuary.  相似文献   

Levee failure mechanisms during the extreme rainfall event: a case study in Southern Taiwan     

Wen-Chao Huang  Meng-Chia Weng  Ray-Kuo Chen 《Natural Hazards》2014,70(2):1287-1307

Extreme weather has recently caused many disasters worldwide. In August 8, 2009, Southern Taiwan suffered from serious floods during Typhoon Morakot. In this extreme rainfall event, the Chiuliao first levee in the Laonong River basin experienced catastrophic failure. Therefore, this study focuses on the levee failure mechanisms based on variations in levee water levels. Specifically, this study investigates four mechanisms based on limit state equilibrium. The first mechanism involves the slope stability under hydrostatic conditions at various water levels. The results of this analysis show that the levee cannot fail under this mechanism. The second mechanism involves the levee slope stability with steady-state seepage. Because the water levels are different on the protected and flood sides, the water recedes much faster on the flood side than the protected side. Based on this analysis, the levee slope might fail when the water level at the protected side is close to the top of levee and the water level at the flood side starts to recede. The third and fourth mechanisms involve the levee foundation failure in terms of sliding and overturning failure. The results of this study indicate that the levee foundation is more prone to sliding failure than overturning failure. Based on these results, this study shows that the levee failed when the water level at the protected side neared the top of levee while the water level at flood side started to recede. At this moment, the levee may fail because of both the slope failure with seepage and sliding failure of the levee foundation.  相似文献   

Towards a rapid assessment of highway slope disasters by using multidisciplinary techniques     

Weng  Meng-Chia  Lin  Cheng-Han  Shiu  Wen-Jie  Chao  Wei-An  Chiu  Chia-Chi  Lee  Ching-Fang  Huang  Wei-Kai  Yang  Che-Ming 《Landslides》2022,19(3):687-701

Mega-earthquakes and extreme climate events accompanied by intrinsic fragile geology lead to numerous landslides along mountain highways in Taiwan, causing enormous life and economic losses. In this study, a system for rapid slope disaster information integration and assessment is proposed with the aim of providing information on landslide occurrence, failure mechanisms, and subsequent landslide-affected areas to the highway authority rapidly. The functionality of the proposed system is deployed into three units: (1) geohazard rapid report (GeoPORT I), (2) multidisciplinary geological survey report (GeoPORT II), and (3) site-specific landslide simulation report (GeoPORT III). After landslide occurrence, the seismology-based monitoring network rapidly provides the initial slope disaster information, including preliminary location, event magnitude, earthquake activity, and source dynamics, within an hour. Within 3 days of the landslide, a multidisciplinary geological survey is conducted to collect high-precision topographical, geological, and remote-sensing data to determine the possible failure mechanism. After integrating the aforementioned information, a full-scale three-dimensional landslide simulation based on the discrete element method is performed within 10 days to reveal the failure process and to identify the areas potentially affected by subsequent disasters through scenario modeling. Overall, the proposed system can promptly provide comprehensive and objective information to relevant authorities after the event occurrence for hazard assessment. The proposed system was validated using a landslide event in the Central Cross-Island Highway of Taiwan.

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Multiproxy Paleosol Evidence for Jurassic Paleoclimate Fluctuations in the Sichuan Basin, SW China     

LI Jun  WEN Xingyue  PAN Yuanyuan  HUANG Chengmin 《《地质学报》英文版》2022,96(6):2105-2124

Paleoclimate reconstruction of continental environments has been hampered by the limited evidence. A thick sequence of Jurassic continental deposits in the Sichuan Basin, Southwest China yields abundant paleosols that may offer valuable insights regarding Jurassic climate scenarios. A succession of 169 paleosols belonging to Protosols, Calcisols, and Argillisols from 23 detailed stratigraphic sections was recognized and characterized macro- and micromorphologically and assessed for mineral and geochemical compositions. Quantitative paleoclimate reconstructions using bulk geochemical proxies, the depth to and the stable oxygen isotopic composition of paleosol carbonates indicated a predominant alternation of semiarid and arid cool/warm-temperate climatic conditions punctuated by several episodes of subhumid and humid climates that generally prevailed in the Sichuan Basin during the Jurassic. The estimated paleoatmospheric CO2 concentrations (pCO2) from calcic paleosols yielded a low range of ~104 ± 58 to ~610 ± 152 ppmv during the Middle Jurassic. The terrestrial paleotemperature changes in the Sichuan Basin coincided with the pCO2 variations, which probably resulted from global geological events (e.g., volcanic activities, magmatic and oceanic events, and the ephemeral caps development) in the Middle Jurassic. Jurassic climatic fluctuations in the basin were likely attributed to true polar wander due to global plate motion, megamonsoon effect linked to global and regional paleogeography, and regional paleotopography.  相似文献   

Drought risk assessment in China with different spatial scales     

Baisha Weng  Ping Zhang  Sinuo Li 《Arabian Journal of Geosciences》2015,8(12):10193-10202

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环渤海区域旅游非均衡发展时空特征研究     

翁钢民  姚昭屹  贾丽丽 《地域研究与开发》2015,(3):91-95

受资源禀赋、地理区位、经济水平等因素的影响,环渤海区域旅游发展水平不尽相同,非均衡性问题日益突显,且差距有拉大的趋势。空间自相关是一种空间统计分析方法,旨在探索旅游要素的空间分布规律和作用机制。根据2004—2013年的数据,计算环渤海地区的接待入境旅游人数、国际旅游外汇收入、国内旅游人数、国内旅游收入4组全局Moran’s I值,分析该时期环渤海区域旅游空间集聚演变过程。在局部空间自相关方面,选取2013年截面数据,通过Moran散点图和LISA分析,探究环渤海区域旅游发展相关程度和集聚情况,为区域旅游发展政策制定提供决策依据。  相似文献   

Influencing domain of peripheral sources in the urban heavy pollution process of Beijing   总被引：1，自引：0，他引：1  

KANG Shichang  Paul A. Mayewski 《中国科学D辑(英文版)》2005,48(4):565-575

Multiple cities in a diveloped economic area may consist of a city cluster,and the difusion and mixing of its pollutants result in the effect of pollutants plume between cities and the large-scale regional pollution diffusion phenomenon.The distant transfer and diffusion of pollutants occurs when massive aerosols are affected by the dynamic porcess of large-scale circulations.Research suggesten that the life span of aerosol particles whose diameters are about 1 um is the longest.The longevity …  相似文献   

气象探空数据动态比对中误差计算方法研究   总被引：1，自引：0，他引：1  

翁锦辉  罗建平  王凡  羊清雯 《气象研究与应用》2010,31(3)

在高空动态数据比对中,需要同时考虑系统误差与随机误差。采用多个探空仪同球比对施放的方法,从相对系统误差、标准偏差等方面,对被试探空仪进行比对评估,同时采取误差分离方法,计算被试探空仪的随机误差。考虑高空温度在对流层与平流层的不同变化趋势,采取细化分层方式进行计算,以反映大气特性。  相似文献