1979-2010年青藏高原积雪深度时空变化遥感分析

积雪深度是表征积雪特征的重要参数,也是区域气候变化最敏感的响应因子之一。利用1979-2010年逐日中国雪深长时间序列数据集,采用GIS空间分析和地统计方法,分析了青藏高原积雪深度的时空变化规律及异常空间分布特征。结果表明：近32年来,青藏高原雪深呈显著增加趋势,增加速率为0.26 cm/10a,其中,昆仑高寒荒漠地带雪深增加最为明显,增加速率达0.73 cm/10a;20世纪80年代至90年代青藏高原雪深呈逐步增加趋势,21世纪初变化平稳;青藏高原4个季节雪深变化均呈现为上升趋势,尤以冬季增加最为明显,增加速率达0.57 cm/10a。青藏高原东南、西部和南部为雪深分布高值区;逐像元回归分析表明,高原雪深呈增加趋势的像元数占全区像元总数的67.1%,其中有91.3%为轻度和中度增加,主要分布在高原北部和西部;最大雪深变化基本维持在-0.1~0.1 cm/a（45.47%）之间,在昆仑北翼山地、柴达木山地、羌塘高寒地带南部等局部地区最大雪深有增加趋势,主要是轻度增加,面积比例为36.66%。果洛那曲高寒地带、青南高寒地带和羌塘高寒地带为青藏高原积雪深度异常变化敏感区。     

CLIMATIC VARIATIONS IN CHINA OVER THE LAST 2000 YEARS

1 INTRODUCTIONIn the last years, evidence for climate changes showed that the timing of the two great climatic events of “Medieval Warm Period” (MWP) and “Little Ice Age” (LIA) differed geographically (HUGHES et al., 1994, JONES and BRADLEY, 1992). In other words, the cold or warm periods in one region were often not coincident with those in other regions. The Northern Hemisphere warmth degree in the Middle Ages was lower than or at most comparable to that in the mid-20…     

CLIMATIC VARIATIONS IN THE COASTALZONE- COMPARISON BETWEEN THE PORIVER DELTA (ADRIATIC SEA, ITALY) ANDTHE HUANGHE RIVER DELTA (BOHAI SEA,CHINA)

The aim of this work is to research the influence of natural climatic changes on the evolution of the coastal zone in modern times and the possible implication of human activities on the configuration of the present coastline.Comparison of data of two very far and different areas , the Po River delta, Adriatic Sea and the Huanghe River delta, Bohai Sea, reveals the planetary diffusion of climatic fluctuations and their effects on coastal evolution .     

Climatic variations in the coastal zone — Comparison between the Po River delta (Adriatic Sea,Italy) and the Huanghe River delta (Bohai Sea,China)

The aim of this work is to research the influence of natural climatic changes on the evolution of the coastal zone in modern times and the possible implication of human activities on the configuration of the present coastline. Comparison of data of two very far and different areas, the Po River delta, Adriatic Sea and the Huanghe River delta, Bohai Sea, reveals the planetary diffusion of climatic fluctuations and their effects on coastal evolution. Contribution No. 820 from the Marine Geology Institute, C. N. R., Italy. Contribution No.2207 from the Institute of Oceanology, Academia Sinica. Project supported by the National Natural Science Foundation of China.     

SWOT宽刈幅干涉测高卫星数值模拟：以南海海平面变化监测为例

以中国南海及周边区域为例,利用ECCO2海洋模式数据模拟的SWOT观测数据评估SWOT的海平面长期观测能力。分析SWOT模拟误差表明,相位误差和横滚误差占主导,并且距离星下点越远误差越大。通过空间平滑对模拟的误差进行消除,南海地区SWOT的观测与海洋模式真值的均方根误差从4 cm降低到2 cm。对SWOT的观测和海洋模式信号进行分析发现,SWOT观测误差的空间分布基本呈南北条带状,这主要受卫星宽刈幅沿轨观测方式的影响,与海平面变化信号强度无关。进一步提取SWOT一条轨迹进行滤波和10 km×10 km网格插值,结果表明,2 km空间分辨率的地转流估计结果受噪声影响较大,而10 km分辨率结果更接近真值。     

Mean properties of mesoscale eddies in the Kuroshio recirculation region

Using a 19-year altimetric dataset, the mean properties and spatiotemporal variations of eddies in the Kuroshio recirculation region are examined. A total of 2 001 cyclonic tracks and 1 847 anticyclonic tracks were identifi ed using a geometry-based eddy detection method. The mean radius was 57 km for cyclonic eddies and was 61 km for anticyclonic eddies, respectively, and the mean lifetime was about 10 weeks for both type eddies. There were asymmetric spatial distributions for eddy generation and eddy termination, which were domain-dependent. Mean eddy generation rates were 2.0 per week for cyclonic eddies and were 1.9 per week for anticyclonic eddies. Both type eddies tended to deform during their lifetime and had different propagation characteristics, which mainly propagated westward and southwestward with velocities 4.0–9.9 cm/s, in the Kuroshio recirculation region. Further discussion illustrates that the eddy westward speed maybe infl uenced by the combined effect of vertical shear of horizontal currents and nonlinearity of eddy. To better understand the evolution of eddy tracks, a total of 134 long-lived tracks(lifetime ≥20 weeks) were examined. Comparison between short-span eddies(lifetime ≥4 weeks and 20 weeks) and long-lived eddies is also conducted and the result shows that the short-span and long-lived eddies have similar time evolution. Finally, eddy seasonal variations and interannual changes are discussed. Correlation analysis shows that eddy activity is sensitive to the wind stress curl and meridional gradient of sea surface temperature on interannual timescales. Besides, the strength and orientation of background fl ows also have impacts on the eddy genesis.     

CHARACTERISTICS OF INTRASEASONAL VARIATIONS IN THE MIXED LAYER OF "WARM POOL" AREAS

Observational data obtained during the TOGA-COARE IOP in the "warm pool" area of the West-ern Tropical Pacific were used to analyze some characteristics of the intraseasonal variations in the mixedlayer. The influence of westerly burst and rainfall on SST, salinity. and mixed layer depth are discussed.There are two pairs of counteracting processes in the "warm pool" mixed layer: (1) The increase of mixedlayer depth caused by local westerly bursts and the decrease of mixed layer depth caused by larger scaleeasterly relaxation;(2) the vertical mixing by local wind and the strong stratification due to rainfall in themixed layer. Some possible mechanisms through the interactions between the intraseasonal time scale varia-tions of the oceanic mixed layer and atmospheric low frequency oscillations are revealed.     

Seasonal and intraseasonal variations of the surface Taiwan Warm Current

To study seasonal and intraseasonal variations of the Taiwan Warm Current (TWC) in detail Rotated Empirical Orthogonal Function (REOF) and Extended Associate Pattern Analysis (EAPA) are jointly adopted with daily sea surface salinity (SSS), sea surface temperature (SST) and sea surface height (SSH) datasets covering 1126 days from American Navy Experimental Real-Time East Asian Seas Ocean Nowcast System in the present paper. Results show that the first and second REOFs of SST in the southern East China Sea (SECS) account for 50.8% and 39.8% of the total variance. The surface TWC contains persistent (multi-year mean), seasonal and intraseasonal components. The persistent one mainly inosculates with the Kuroshio but the seasonal and intraseasonal ones are usually active only on the continental shelf. Its persistent component is produced by inertial flow of the Kuroshio, however its seasonal and intraseasonal ones seems coming from seasonal and intraseasonal oscillations of monsoon force. The seasonal one reaches its maximum in late summer,lasting about four months and the intraseasonal one takes place at any seasons, lasting more than 40 days.     

Analysis of seasonal variation of water masses in East China Sea

Seasonal variations of water masses in the East China Sea （ECS） and adjacent areas are investigated, based on historical data of temperature and salinity （T-S）. Dynamic and thermodynamic mechanisms that affect seasonal variations of some dominant water masses are discussed, with reference to meteorological data. In the ECS above depth 600 m, there are eight water masses in summer but only five in winter. Among these, Kuroshio Surface Water （KSW）, Kuroshio Intermediate Water （KIW）, ECS Surface Water （ECSSW）, Continental Coastal Water （CCW）, and Yellow Sea Surface Water （YSSW） exist throughout the year. Kuroshio Subsurface Water （KSSW）, ECS Deep Water （ECSDW）, and Yellow Sea Bottom Water （YSBW） are all seasonal water masses, occurring from May through October. The CCW, ECSSW and KSW all have significant seasonal variations, both in their horizontal and vertical extents and their T-S properties. Wind stress, the Kuroshio and its branch currents, and coastal currents are dynamic factors for seasonal variation in spatial extent of the CCW, KSW, and ECSSW, whereas sea surface heat and freshwater fluxes are thermodynamic factors for seasonal variations of T-S properties and thickness of these water masses. In addition, the CCW is affected by river runoff and ECSSW by the CCW and KSW.     

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东莞内陆自然水域鱼类资源变动的调查与分析

调查东莞内陆自然水域1982-1984和2005-2010年的鱼类资源。结果显示,1982-1984年,有鱼类151种,分隶17目44科,其中洄游性鱼类8种,河口性鱼类47种。纯淡水鱼类中,鲤形目67种,鲇形目14种,组成东莞纯淡水鱼类的主体,约占84.4%;河口鱼类中,鲈形目26种,与鲱、鲻形目组成东莞沿岸、三角洲水网咸淡水鱼类的主体,约占76.7%。鲤形目、鲈形目和鲇形目组成东莞内陆自然水域原生态鱼类的主体,约占鱼类总数的80.1%。2005-2010年的复查结果,仅存鱼类107种,分隶18目40科,其中原土著鱼类96种,隶属15目34科。近30年间,有2目10科56种土著鱼类消失,减少37.1%,生物多样性下降;外来入侵鱼类增多3目6科11种,从原先占有比例的2.6%增至14%。分析主要经济鱼类的生物学特征以及鱼类资源变动原因,探讨鱼类资源的利用、增殖和保护。     

The link between interannual variation of the South China Sea summer monsoon onset and summer precipitation in Shandong Province

Relationship between the onset date of South China Sea (SCS) summer monsoon and the summer rainfall in Shandong Province was examined by comprehensive analysis to establish a conceptual model of the link. If the summer monsoon occurs earlier, the 500 hPa level would induce the teleconnection of Eurasian pattern in the summer (June-August), which indicates that the western Pacific subtropical high is displaced northward further than usual, the Siberian high is intensified and the Okhotsk low is deepened. Under such circumstance, Shandong, located in the west side of the subtropical high and in front of the mid-Siberia high, would be expected to have a wet summer because it is quite possible for cold and warm air to meet and interact with each other in Shandong. Statistical analysis revealed that the 500 hPa anomalies over Korea and Japan were sensitive to the SCS monsoon onset date and very important to precipitation in Shandong, and that the convective activities over the deep water basin in the SCS in 24-26 pentads significantly influenced the position of the ridge line of the western Pacific subtropical high. These findings yielded better understanding of the causative mechanisms involved in the precipitation generation, so that the knowledge gained can possibly be applied for long-lead forecast.     

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六盘水市土壤侵蚀时空特征及影响因素分析

六盘水市是我国生态地位极其重要,水土流失又较为严重的城市。近些年,六盘水市实施了一系列生态工程,为了定量分析六盘水市土壤侵蚀状况及其影响因素,本文基于RUSLE模型,利用降雨数据、遥感影像数据、土地利用数据等,对贵州省六盘水市1990-2015年土壤侵蚀模数和土壤侵蚀量进行定量模拟,分析其时空动态变化,利用地理探测器定量分析影响因素,并进行空间相关性分析,结果表明： ① 六盘水市土壤侵蚀以微度和中度侵蚀为主。土壤侵蚀严重地区主要分布在北盘江流域与南盘江流域交界处以及喀斯特山地地区,煤矿开采使植被覆盖等抑制土壤侵蚀因子减少作用,使局部地区土壤侵蚀程度加剧。② 1990-2010年平均土壤侵蚀模数整体为下降趋势,2010-2015年为上升趋势。其中2000年平均土壤侵蚀模数最大,2010年平均土壤侵蚀模数最小。该变化由降雨可蚀性因子和植被覆盖度因子综合影响所致。③ 植被覆盖度因子和多年平均降雨量因子是影响区域土壤侵蚀空间分布的重要因素。未利用土地、植被覆盖度小于0.3、坡度在25°以上和降雨量在1543~1593 mm之间的地区为高风险侵蚀区域。④ 植被覆盖度与土壤侵蚀在空间上全部呈负相关性,降雨因子与土壤侵蚀在空间上存在负相关性和正相关性。⑤ 土壤侵蚀改善区域大多分布在生态工程区域内,生态工程建设能够改善土壤侵蚀情况,不同生态工程保护侧重点不同导致土壤侵蚀改善程度不同。退耕还林还草工程对六盘水市土壤侵蚀的改善具有重要意义,六盘水市更宜退耕还林。     

EFFECTS OF SEASONALITY ON STREAMFLOW AND WATER QUALITY OF THE PINANG RIVER IN PENANG ISLAND, MALAYSIA

For the Pinang River, originating in the western highlands of Penang Island, the nature, sources and extent of pollution were studied. The river water samples collected at five selected sites were analyzed for various physical and chemical parameters, namely temperature, DO, BOD, COD, SS, pH, ammoniac nitrogen (AN), and conductance. Long-term data of rainfall and temperature were analyzed to determine the seasonal variations of the streamflow.The streamflow during the dry season is extremely low compared to the wet season, thus concentrations of contaminants derived from point pollution source increase due to lack of rainfall and runoff events. On the contrary, in the predominantly urban and agricultural catchments, non-point pollution source increases during rainy season through seepage and runoff. Effects of seasonal variations consequently deterrnine the quantity and quality of the water parameters.The Jelutong River, the Dondang River and the Air Itam River carry the seepage from widely urban and residential areas to the main Pinang River systems. Water quality of the Pinang River at different points assessed by the water quality indices was compared. According to the quality indices during the study period, water quality in the upper reaches of the river is medium to good. It dwindled in the plains, due to the seepage from urban areas and discharges from the industrial and agricultural lands.     

A numerical study on seasonal variations of the Taiwan Warm Current

Princeton Ocean Model (POM) is employed to investigate the Taiwan Warm Current (TWC) and its seasonal variations. Results show that the TWC exhibits pronounced seasonal variations in its sources, strength and flow patterns. In summer, the TWC flows northeast in straight way and reaches around 32°N; it comes mainly from the Taiwan Strait, while its lower part is from the shelf-intrusion of the Kuroshio subsurface water (KSSW). In winter, coming mainly from the shelf-intrusion of the Kuroshio northeast of Taiwan, the TWC flows northward in a winding way and reaches up around 30°N. The Kuroshio intrusion also has distinct seasonal patterns. The shelf-intrusion of KSSW by upwelling is almost the same in four seasons with a little difference in strength; it is a persistent source of the TWC. However, Kuroshio surface water (KSW) can not intrude onto the shelf in summer, while in winter the intrusion of KSW always occurs. Additional experiments were conducted to examine effects of winds and transport through     

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THE DEPENDENCE OF WIND STRESS ON SEA STATE

Based on up to date literature, this paper details the evolution of wave dependence of wind stress.Some typical models of the dependence of wind stress on waves are described in detail. Although there isno universally accepted theory and model, recent studies indicate that the wind strees strongly dependson the development state of sea waves, i. e., young seas are rougher than mature seas, in other words, thewind stress decreases with increasing wave age.     

Diagnostic model construction and example analysis of habitat degradation in enclosed bay: II. spatiotemporal variations in habitat degradation in Sansha Bay

The process of habitat degradation varies in habitat type and driving force which shows certain spatial and temporal heterogeneity on regional scales. In the present study, a new diagnostic model for enclosed bay habitat degradation was established, with which the spatial and temporal variation patterns of habitat degradation during 1991–2012 in Sansha Bay, Fujian, China was investigated. The results show that anthropogenic disturbance is the major controlling factor for the habitat degradation in large temporal heterogeneity in the bay. On the other hand, the habitat degradation experienced signifi cant spatial variations among six sub-bays. Under the joint action of temporal and spatial heterogeneity, the degradation trend in growing scale shows a more signifi cant correlation with the distribution of local leading industries along shorelines. Therefore, we quantifi ed the main characters of habitat degradation in Sansha Bay, and have understood the relationship between the status of habitats spatio-temporal variation value and the main controlling factor leading to the changes. However, a defi ciency of this research is the lack of or inaccessible to the detailed data, which shall be better solved in the future study for accessing more data from more sources.