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991.
东亚夏季大气环流和气候对冬季海温异常的邻响应和遥响应 总被引:1,自引:1,他引:0
本文通过IAP-GCM的数值模拟,研究了全球大气环流对黑潮海域和赤道东太平洋冬季SST异常的响应,并着重比较东亚大气环流和气候对黑潮区SSTA的响应(邻响应)和对赤道东太平洋SSTA的响应(遥响应)。首先,无论是黑潮区SSTA引起的邻响应还是赤道东太平洋SSTA所引起的遥响应对东亚大气环流和气候变化的影响都是明显而重要的。由于在大气中低频振荡被激发出来,其响应将持续较长时间。进一步分析表明,东亚大气环流对黑潮区或赤道东太平洋冬季正SSTA的响应都将造成华北地区夏季的多雨,其数值模拟结果与观测相一致。另外,赤道西太平洋地区大气的异常(尤其是对流活动)对于东亚地区大气环流和气候变化有重要作用 相似文献
992.
993.
遥感在1998年洪水监测中的作用 总被引:9,自引:0,他引:9
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994.
Through the water areas extracted from remote sensing images and the combination of the methods for establishing the formula for calculating tidal influx with tidal data, the tidal influx of the Haikou Bay, Hainan Province was found to be 5.14×107m3 in 1990, 5.80×107m3 in 1984 and 5.05×107m3 in 1965, respectively.After the analysis of the morphological and tidal range factors which determine tidal influx, this paper presents the trend of the changes in tidal influx caused by the changes in the morphological factors of the Haikou Bay.It is found that a decreasing trend was shown with a depressive rate of 2×10-3during the period from 1965 to 1984, and an increasing trend with an incremental rate of 1×10-3 during the period of 1984-1990.The main reason for the appearance of the decreasing trend before 1984 is the natural deposition and silting-up of the bay sediments; after 1984, the dredging and expansion of the Haikou Port and the Haikou New Port which caused an increase in water area at the mean low tide are the leading factor which causes the increase in tidal influx. 相似文献
995.
In order to examine the applicability of remotely-sensed ocean color for the estimation of phytoplankton biomass and primary
production in the Oyashio region, the western subarctic Pacific, vertical distributions of chlorophylla concentration and primary production were observed in April and May 1997. Spring bloom was observed in both April and May,
and the surface concentration of chlorophylla exceeded 40 mg m−3. The relationship between the standing stocks of chlorophylla within the layer from the sea surface to one optical depth (0–1/k layer) and the surface chlorophylla concentration is expressed as a Michaelis-Menten equation. The mean ratio of the standing stock of chlorophylla in the euphotic layer to that in the 0–1/k layer was 4.41, this ratio did not significantly differ from 4.61 which was obtained at homogeneous distribution of chlorophylla within the euphotic layer. These facts suggest that the distribution of chlorophylla could be assumed to be homogeneous in the euphotic layer during the spring bloom. Results of primary production measurements
by simulatedin situ method were compared with those by an algorithm with two variables; chlorphylla and non-spectral PAR. Daily primary production in the euphotic layer estimated by the algorithm varied in a range of 38–274%
of that estimated by incubation, although the primary productions by the algorithm agreed with those by the incubation at
a half of stations. Primary production within the euphotic layer calculated using simply the surface data was the same as
that estimated using vertical distribution of chlorophylla. These results show that the primary production in the euphotic layer may be estimated from the remote sensed measurements
during the spring bloom in the Oyashio region. 相似文献
996.
Hajime Fukushima Akiko Higurashi Yasushi Mitomi Teruyuki Nakajima Toshimitsu Noguchi Toshio Tanaka Mitsuhiro Toratani 《Journal of Oceanography》1998,54(5):417-430
This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic
structure with Gordon and Wang’s Sea WiFS algorithm, it uses 10 candidate aerosol models including the “Asian dust model”
introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670
and 865 nm bands, the algorithm selects a pair of aerosol models that account best for the observed spectral reflectances,
and synthesizes the aerosol reflectance used for the atmospheric correction. Two different schemes for determining the value
of the parameter for the aerosol model selection are presented and their anticipated estimation error is analyzed in terms
of retrieved water reflectance at 443 nm. The results of our numerical simulation show that the standard deviation of the
estimation error of the “weighted average” scheme is mostly within the permissible level of ±0.002, reducing the error by
18% on average compared to the “simple average” scheme. The paper further discusses the expected error under the old CZCS-type
atmospheric correction, which assumes constant aerosol optical properties throughout the given image. Although our algorithm
has a better performance than the CZCS algorithm, further analysis shows that the error induced by the assumption taken in
the algorithm that the water-leaving radiance at 670 nm band is negligibly small may be large in high pigment concentration
waters, indicating the necessity for future improvements. 相似文献
997.
998.
999.
本文针对遥感信息的数据特征探讨了卫星遥感信息处理与多元统计算法之间的关系,并从实际出发对最小二乘残差技术,目标模式识别,增强主成份分析等方法的应用作了介绍。 相似文献
1000.
简要介绍了水土流失定量遥感方法的组成和基本原理,重点叙述了它在小流域治理试区的应用作业和应用结果,并讨论了它的适应性、准确性、实用性和应用前景等。该法的监测模型可与美国近年刊出的RUSLE相媲美,且其因子算式算法系由我国实测资料所建,故更适合我国水土流失实际的应用效果,尤其适用于遥感和GIS数据的微机处理。其应用结果,不仅有比常规调查法和定性遥感法更准确实用的流失总量、各级面积的统计数据和流失现状图,而且还有流失治理规划的防治强度预报图。在UNDP试区应用表明,该法所建立的系统,也可对小流域(大于7km2)每年实施监测,以获水土流失变化动态的准确信息。 相似文献