排序方式： 共有21条查询结果，搜索用时 671 毫秒
1.
Application of satellite infrared data for mapping of thermal plume contamination in coastal ecosystem of Korea 总被引：3，自引：0，他引：3
The 5900 MW Younggwang nuclear power station on the west coast of Korea discharges warm water affecting coastal ecology [KORDI report (2003). Wide area observation of the impact of the operation of Younggwang nuclear power plant 5 and 6, No. BSPI 319-00-1426-3, KORDI, Seoul, Korea]. Here the spatial and temporal characteristics of the thermal plume signature of warm water are reported from a time series (1985-2003) of space-borne, thermal infrared data from Landsat and National Oceanic and Atmospheric Administration (NOAA) satellites. Sea surface temperature (SST) were characterized using advanced very high resolution radiometer data from the NOAA satellites. These data demonstrated the general pattern and extension of the thermal plume signature in the Younggwang coastal areas. In contrast, the analysis of SST from thematic mapper data using the Landsat-5 and 7 satellites provided enhanced information about the plume shape, dimension and direction of dispersion in these waters. The thermal plume signature was detected from 70 to 100 km to the south of the discharge during the summer monsoon and 50 to 70 km to the northwest during the winter monsoon. The mean detected plume temperature was 28 degrees C in summer and 12 degrees C in winter. The DeltaT varied from 2 to 4 degrees C in winter and 2 degrees C in summer. These values are lower than the re-circulating water temperature (6-9 degrees C). In addition the temperature difference between tidal flats and offshore (SSTtidal flats - SSToffsore) was found to vary from 5.4 to 8.5 degrees C during the flood tides and 3.5 degrees C during the ebb tide. The data also suggest that water heated by direct solar radiation on the tidal flats during the flood tides might have been transported offshore during the ebb tide. Based on these results we suggest that there is an urgent need to protect the health of Younggwang coastal marine ecosystem from the severe thermal impact by the large quantity of warm water discharged from the Younggwang nuclear power plant. 相似文献
2.
3.
Dongju Peng Hindumathi Palanisamy Anny Cazenave Benoit Meyssignac 《Marine Geodesy》2013,36(2):164-182
Spatial patterns of interannual sea level variations in the South China Sea (SCS) are investigated by analyzing an EOF-based 2-dimensional past sea level reconstruction from 1950 to 2009 and satellite altimetry data from 1993 to 2009. Long-term tide gauge records from 14 selected stations in this region are also used to assess the quality of reconstructed sea levels and determine the rate of sea level along the coastal area. We found that the rising rate of sea levels derived from merged satellite altimetry data during 1993–2009 and past sea level reconstruction over 1950–2009 is about 3.9 ± 0.6 mm/yr and 1.7 ± 0.1 mm/yr, respectively. For the longer period, this rate is not significantly different from the global mean rate (of 1.8 ± 0.3 mm/yr). The interannual mean sea level of the SCS region appears highly correlated with Niño 4 indices (a proxy of El Niño-Southern Oscillation/ENSO), suggesting that the interannual sea level variations over the SCS region is driven by ENSO events. Interpolation of the reconstructed sea level data for 1950–2009 at sites where tide gauge records are of poor quality (either short or gapped) show that sea level along the Chinese coastal area is rising faster than the global mean rate of 1.8 mm/yr. At some sites, the rate is up to 2.5 mm/yr. 相似文献
4.
B. Meyssignac C. G. Piecuch C. J. Merchant M.-F. Racault H. Palanisamy C. MacIntosh S. Sathyendranath R. Brewin 《Surveys in Geophysics》2017,38(1):187-215
We analyse the regional variability in observed sea surface height (SSH), sea surface temperature (SST) and ocean colour (OC) from the ESA Climate Change Initiative datasets over the period 1993–2011. The analysis focuses on the signature of the ocean large-scale climate fluctuations driven by the atmospheric forcing and do not address the mesoscale variability. We use the ECCO version 4 ocean reanalysis to unravel the role of ocean transport and surface buoyancy fluxes in the observed SSH, SST and OC variability. We show that the SSH regional variability is dominated by the steric effect (except at high latitude) and is mainly shaped by ocean heat transport divergences with some contributions from the surface heat fluxes forcing that can be significant regionally (confirming earlier results). This is in contrast with the SST regional variability, which is the result of the compensation of surface heat fluxes by ocean heat transport in the mixed layer and arises from small departures around this background balance. Bringing together the results of SSH and SST analyses, we show that SSH and SST bear some common variability. This is because both SSH and SST variability show significant contributions from the surface heat fluxes forcing. It is evidenced by the high correlation between SST and buoyancy-forced SSH almost everywhere in the ocean except at high latitude. OC, which is determined by phytoplankton biomass, is governed by the availability of light and nutrients that essentially depend on climate fluctuations. For this reason, OC shows significant correlation with SST and SSH. We show that the correlation with SST displays the same pattern as the correlation with SSH with a negative correlation in the tropics and subtropics and a positive correlation at high latitude. We discuss the reasons for this pattern. 相似文献
5.
Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes 总被引：1，自引：0，他引：1
Weiqing Han Gerald A. Meehl Detlef Stammer Aixue Hu Benjamin Hamlington Jessica Kenigson Hindumathi Palanisamy Philip Thompson 《Surveys in Geophysics》2017,38(1):217-250
Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth’s climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modes and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this paper, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR. 相似文献
6.
Balasubramanian Sundarabalan Palanisamy Shanmugam Yu-Hwan Ahn 《Ocean Science Journal》2016,51(1):67-86
Modeling of the wave-induced underwater light fluctuations at near-surface depths in coastal oceanic waters is challenging because of the surface roughness and strong anisotropic effects of the light field. In the present work, a simple and computationally efficient radiative transfer model is used for the wind-driven sea surface for simulating underwater light fields such as downwelling irradiance (Ed), upwelling irradiance (Eu), and upwelling radiance (Lu) in a spatial domain. It is an extension of our previous work that essentially combines the air–sea interface of the wind-driven sea surface with transmittance and reflectance along with the diffuse and direct components of the homogenous and inhomogeneous water column. The present model simulates underwater light fields for any possible values of absorption and backscattering coefficients. To assess the performance of the model, the Ed, Eu, and Lu profiles predicted by the model are compared with experimental data from relatively clear and turbid coastal waters. Statistical results show significantly low mean relative differences regardless of the wavelength. Comparison of the simulated and in-situ time series data measured over rough sea surfaces demonstrates that model-observation agreement is good for the present model. The Hydrolight model when implemented with the modified bottom reflectance and phase function provides significantly better results than the original Hydrolight model without consideration of the bottom slope and vertically varying phase function. However, these results are non-spatial and have errors fluctuating at different wavelengths. To further demonstrate the efficiency of the present model, spatial distribution patterns of the underwater light fields are simulated based on the measured data from a coastal station for different solar zenith angles (under sunny condition). Simulated wave-induced fluctuations of the underwater lights fields show a good consistency with in-situ data for a few near-surface depths. The present model also provides a reasonable approximation for simulating wave-induced effects on the downward irradiance field and its anisotropic conditions caused by the surface roughness, wavelength and angle of incidence. 相似文献
7.
8.
India’s surface water and groundwater distribution is temporally variable due to the monsoon. Agriculture is one of the dominant economic sectors in India. Groundwater quality is regularly assessed to determine usability for drinking and irrigation. In this study, World Health Organization and Bureau of Indian Standards guidelines were used to determine suitability of groundwater near artificial recharge structures (ARS) with a focus on the structures´ impact on groundwater quality. Groundwater resources were evaluated for irrigation suitability using electrical conductivity (EC), sodium adsorption ratio, the US Salinity Laboratory diagram, sodium concentration, Wilcox’s diagram, Kelly’s index, and Doneen’s permeability index. EC and major ions were tested in recharge areas at different distances from the ARS. The construction of ARS at optimal distances along major streams has improved groundwater quantity and quality in the sub-basin. Before construction of ARS, fluoride concentrations were higher; after construction, fluoride was reduced in most locations. Water stored in the check dam and groundwater in the wells closer to the structure were suitable for both drinking and irrigation purposes. Impact of ARS on nearby groundwater quality was observed at Pallipatti, Mulayanur, Venkadasamuthram, Pudupatti, Poyyappatti, Harur1, and Sekkampatti. More distant sites included Pappiredipatti, Nambiyappati, Menasi, Harur, Todampatti, and Adikarapatti. Data demonstrated improved groundwater quality in the area of the ARS. Through recharge, the non-potable fluoride in the region is reduced to the permissible limit for human consumption. 相似文献
9.
10.
Palanisamy Shanmugam Yu-Hwan Ahn Joo-Hyung Ryu Balasubramanian Sundarabalan 《Journal of Oceanography》2010,66(6):815-830
This study was aimed to investigate three inversion models (currently in use with Moderate Resolution Imaging Spectroradiometer
and Sea-viewing Wide Field-of-view Sensor data processing), namely constrained Linear Matrix (LM), Quasi-analytical algorithm
(QAA) and GSM semi-analytical models (GSM). These models were applied to large bio-optical data sets (collected from coastal
and open sea waters around Korea) to retrieve inherent optical properties (IOPs) such as absorption coefficients of phytoplankton
(a
ph
), colored dissolved and detrital organic matters (a
cdm
), and particulate backscattering coefficient (b
bp
) at five wavelengths (412, 443, 490, 510, and 555 nm). The derived IOP products were compared with in situ a
ph
, a
cdm
and b
bp
coefficients measured for the same remote sensing reflectance (R
rs
(λ)) data sets used in the models and the uncertainties of the three models were assessed based on the standard statistical
procedures (mean relative error MRE, root mean square error RMSE, slope, and coefficient of determination R
2). It was found that all the three models tended to yield significant errors with varying magnitude at different wavelengths.
Overall performance of the models assessed based on the above statistical means was found in the following order: LM > GSM
> QAA for retrieving the a
ph
, LM > GSM > QAA for retrieving the a
cdm
, and QAA > GSM > LM for retrieving the b
bp
. Our analyses suggest that these models will require additional refinements with a full parameterization by a fully suited
data set in order to produce accurate retrievals of IOPs in coastal and open sea waters around Korea. 相似文献