湖泊富营养化遥感监测研究进展

通过对近年来国内外应用遥感技术对湖泊富营养化监测及评价的研究情况进行了广泛的收集和分析,简述了湖泊富营养化遥感监测的基本原理,总结了湖泊富营养化多光谱遥感与高光谱遥感成果,提出了今后的重点研究方向.     

太湖水华的遥感分析

随着太湖流域的经济迅速发展,太湖湖体的富营养化程度日趋严重,特别是在20世纪的后期,水华频繁爆发。国家环保总局常规的水质监测是基于21个点位对全湖进行评价,完成一次采样耗时近1月,其对大面积水华现象的监测具有很大的局限性。文章利用遥感技术快速、大尺度、动态监测的特点,基于多个时相的TM影像对太湖的水温、悬浮物、叶绿素等水质参数的浓度和分布进行了遥感反演,进而对太湖水华的成因、发展程度、影响因素等方面进行分析,从而对太湖水华发生的特点,太湖的水质情况有一个全面的了解。     

基于Sentinel-2 MSI影像的河湖系统水体悬浮物空间分异遥感监测:以安徽省升金湖与连接长江段为例

开展河湖系统悬浮物监测对掌握水体泥沙运移规律、制定水环境治理措施具有重要意义.以安徽省升金湖与连接长江段水体为研究区,根据实测光谱模拟Sentinel-2 MSI影像波段反射率,结合同步水体悬浮物实测数据建立反演模型;而后根据2017～2019年28景MSI影像水体悬浮物反演结果,分析河湖系统水体悬浮物浓度的变化规律,并探究水位变化对其空间分异的影响.结果表明:①根据MSI影像第六波段与第三波段的比值建立的二次多项式模型具有较高的反演精度(R²=0.863,RMSE=22.211 mg·L^-1),适用于高浊度水体悬浮物反演;②在空间上,升金湖入湖口附近、上中湖区西北部和下湖悬浮物浓度相对较高,除夏季外升金湖悬浮物浓度均高于其连接长江段;在时间上,升金湖悬浮物浓度在夏季相对较低,在其他季节较高,而与其连接的长江水体呈现相反的年内变化规律;③闸控影响下河湖连通性改变造成的水位变化,是影响升金湖-长江悬浮物空间分异的关键因素.在平水期与枯水期,升金湖对长江悬浮物浓度变化具有一定的贡献度,而在丰水期,升金湖与长江悬浮物浓度变化之间的相关性不明显.     

环境卫星CCD与Landsat TM影像质量及生态监测应用比对研究——以青海湖区域为例

针对环境卫星 CCD 影像,结合影像质量评价、专题制图、土地利用/覆被解译以及常用植被指数构建,以青海湖区域为例,与Landsat TM影像进行比对研究。结果表明,在与TM影像质量评价参数比较中,TM影像较优,而环境卫星影像具有很大的改善空间;在对地物判译中,环境卫星影像色彩稍暗淡,但对大多数地物解译判读的边界更清晰;环境卫星覆盖度大,区域制图的优势非常明显;生态监测定量遥感常用的植被指数比较中两种数据大致相同。     

泸沽湖区特殊自然社会生态系统的危机因素及调控途径

通过野外实地考察和对室内资料的分析，探讨了川、滇交界泸沽湖摩梭人聚居区自然社会生态系统的危机因子，并提出了切实可行的调控途径。     

江西省兴国县土壤侵蚀动态监测研究

介绍发应用遥感技术和调查资料编制的江西省兴国县三个时期（１９５８，１９７５，１９８８年）的土壤侵蚀动态监测图。结果表明，建国以来，该县水土流失的动态变化基本上呈抛物线的态势发展，目前水土流失面积在缩小，程度在降低，总的趋势向好的方向发展。     

LAKE EVAPORATION STUDIES USING SATELLITE THERMAL INFRARED DATA1

Thermal infrared radiation data were acquired by the Heat Capacity Mapping Mission (HCMM) satellite over the surface area (385 km²) of Utah Lake during periodic overpasses in 1978 and 1979. The thermal infrared data were converted to lake surface temperatures which were subsequently used in correlations with lake evaporation. Correlations between HCMM surface temperature and pan-derived evaporation exceeded r = 0.90 when HCMM night and day/night average temperatures and two-day average evaporation values were tested. Similar regression studies were done using monthly data from a conceptual evaporation model and the evaporation pan versus monthly HCMM temperature data. In this test both the HCMM day and night monthly temperature versus the monthly model or pan evaporation had correlations exceeding r = 0.95. Empirical estimates of both short and long term lake evaporation using satellite thermal infrared data seem feasible. Attempts to use the HCMM thermal information as direct input to a theoretical approach to calculating evaporation were inconclusive; however, a definite potential seems to exist.     

AN ALGORITHM FOR ESTIMATING SURFACE SUSPENDED SEDIMENT CONCENTRATIONS WITH LANDSAT MSS DIGITAL DATA1

ABSTRACT: Algorithms for Landsat MSS digital data are needed to reduce the necessity of calibrating each Landsat scene if these data are to be useful in monitoring programs for surface suspended sediments. In this study digital data were extracted from 16 Landsat Multispectral Scanner (MSS) scenes collected between March 1987 and August 1988 over Enid Reservoir in North Central Mississippi. These data were converted to radiance and reflectance data for comparison with field measurements of surface suspended sediment concentrations. Concentrations ranged from 2 to 168 mg/1 during the study with only four greater than 100 mg/l. Linear and polynomial regression analyses were used to relate the surface suspended sediment concentrations with radiance and reflectance. Reflectance in MSS band 2 (0.6 to 0.7 μm) and MSS band 3 (0.7 to 0.8 μm) were best related to the surface suspended sediment concentrations with coefficients of determination accounting for 71 percent and 68 percent of the variation in the data, respectively. Regressions with radiance data accounted for 36 percent (band 2) or less of the variation. Logarithmic transformations of either reflectance or sediment concentrations increase the coefficients of determination for MSS band 2 reflectance data to 81 percent. Regressions between the ratio of MSS band 1 to MSS band 2 reflectances and concentrations also accounted for 80 percent of the variation. An equation Log_e SS (mg/l) = 9.21R½+ 2.71R½2 + 8.45, where S is surface suspended sediment concentrations and R¹/₂ is the ratio of MSS band 1 to MSS band 2 reflectances, provided the best fit to the data with a coefficient of determination of 0.82. This equation is essentially the same as an algorithm proposed by Topliss et at. (1990), for estimating surface suspended sediment concentrations in Canadian coastal waters. These equations for Enid Reservoir and Canadian waters suggest that it may be possible to develop an algorithm for widespread use for estimating surface suspended sediments.     

WOODY VEGETATION AND RIPRAP STABILITY ALONG THE SACRAMENTO RIVER MILE 84.5–1191

ABSTRACT: Stability of vegetated and bare riprap revetments along a Sacramento River reach during the flood of record was assessed. Revetment damages resulting from the flood were identified using records provided by the U.S. Army Corps of Engineers and verified by contacts with local interests. Vegetation on revetments along a 35.6-mile reach was mapped using inspection records and stereo interpretation of aerial phoths taken shortly before and after the flood. A follow-up field inspection was conducted in September 1989. Revetment age, material, bank curvature, vegetation, and damage were mapped from a boat. Mapping results from both 1986 and 1989 were placed in a data base. About 70 percent of the bank line of the study reach was revetted. About two-thirds of the revetment was cobble; one-third was quarry stone. Revetment vegetation varied from none to large (> 50-inch diameter) cotton-woods. About 10 percent of the revetted bank line supported some type of woody vegetation. Damage rates for revetments supporting woody vegetation tended to be lower than for unvegetated revetments of the same age located on banks of similar curvature. Chisquared tests indicated damage rates were greater for older (pre-1950 construction) revetments, but were unable to detect differences based on vegetation or bank curvature. Research is needed to generate design criteria and construction techniques to allow routine use of woody plants in bank protection structures.     

DEVELOPMENT AND TESTING OF A SNOWMELT-RUNOFF FORECASTING TECHNIQUE1

ABSTRACT: The snowmelt-runoff model (SRM) was used to produce accurate simulations of streamfiow during the snowmelt period (April-September) for ten years on the Rio Grande Basin (3419 km²) near Del Norte, Colorado, U.S.A. In order to use SRM in the forecast situation, it was necessary to develop a family of snow cover depletion curves for each elevation zone based on accumulated snow water equivalent on April 1. Selection of an appropriate curve for a particular year from snow course measurements allows input of the daily snow cover extent to SRM for forecast purposes. Data from three years (1980, 1981, and 1985) were used as a quasi-forecast test of the procedure. In these years forecasted snow cover extent data were input to SRM, but observed temperature and precipitation data were used. The resulting six-month hydrographs were very similar to the hydrographs in the ten simulation years previously tested based on comparisons of performance evaluation criteria. Based on this result, the Soil Conservation Service (SCS) requested SRM forecasts for 1987 on the Rio Grande. Using the same procedure but with SCS estimated temperature and precipi-tation data, SRM produced a forecast hydrograph that had a r²= 0.82 and difference in seasonal volume of 4.4 percent. To approximate actual operational conditions, SRM computed daily flows were updated every seven days with measured flows. The resulting forecast hydrograph had a R²= 0.90 and a difference in volume of 3.5 percent. The method developed needs to be refined and tested on additional years and basins, but the approach appears to be applicable to operational runoff forecasting using remote sensing data.