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Abnormal Oceanic Conditions Caused by Typhoons Around the Korean Peninsula
Abstract
Abnormal oceanic conditions associated with the passage of typhoons are examined using hydrographic and satellite data 1990-2002. During the passage period of typhoons in the Korean waters, an abrupt decrease of sea surface temperature (SST) in range of 5 to was observed. The areas of SST decrease were an order of 100-200 km, and the low SST lasted about 15-25 days after passage of typhoon. After passage of typhoon, the water temperatures in the surface mixed layer of 30 m show negative anomalies for quite a long period. In addition, stratification parameters were substantially decreased and chlorophyll a density was rapidly increased.
... 은 상대적으로 해수면 온도가 높은 25 30 수온분포 해역에서 세력이 커진다 (Eagleman, 1985;Miller, 1985;Kang and Suh, 1986;Emanuel, 1987;Emanuel, 1988;Evans, 1993;Suh et al., 2003). Suh et al.(2002) (Jordan, 1964;Leipper, 1967;Wright, 1969;Fedorov et al., 1979;Hong and Sohn, 2004). ...
In this study, the wind direction and the wind speed of the nearest temperature observations point of the National Weather Service was analyzed in order to investigate the rapid rise and drop of water temperature in the East Coast appeared after passing of the 2015 typhoon No. 9 and 11. Then the figures were simulated and analyzed using the WRF(weather research and forecast) model to investigate in more detailed path of the typhoon as well as the changes in the wind field. The results were as follows. A sudden drop of water temperature was confirmed due to upwelling on the East coast when ninth typhoon Chanhom is transformed from tropical cyclones into extra tropical cyclone, then kept moving eastwards from Pyongyang forming a strong southerly wind after 13th and this phenomenon lasted for two days. The high SST(sea surface temperature) is confirmed due to a strong northerly wind by 11th typhoon Nangka. This strong wind directly affected the east coast for three days causing the Ekman effect which transported high offshore surface waters to the coast. The downwelling occurred causing an accumulation of high temperature surface water. As a results, the SST of 15m and 25m rose to that of 5m.
Sea surface cooling (SSC) with the passage of typhoons is examined in the East Sea using the Japan Meteorological Agency buoy data (37^{\circ}45`N,\;134^{\circ}23`E) during 1983-2000 and a three-dimensional primitive equation model (the Princeton Ocean Model). Forty typhoons in this period induced the SST decrease ranging from about -0.5^{\circ}C\;to\;-4.3^{\circ}C. Intense SSC $( The model well reproduces prominent features in the observation and addresses how it happens; SSC is induced mainly by momentum mixing effect stirred with the typhoon rather than upwelling.
A remarkable sea surface cooling (SSC) event was observed in the eastern sea of Korean peninsula based on new generation sea surface temperature (NGSST) satellite images in September 2005, when typhoon Nabi passed over the East Sea. The degree of SSC ranged from , and its maximum was observed in the southeastern sea area. Daily variations in sea surface temperature at a longitudinal line , derived from satellite data for September 1-13, 2005, showed that the SSC lasted about 3 days after the typhoon passed in the south of , whereas it was unclear in the north of. Water temperature measured by a mooring buoy suggested that the SSC was caused mainly by a vertical mixing of the water column driven by the typhoon, rather than by coastal upwelling.
A large data set containing coincident in situ chlorophyll and remote sensing reflectance measurements was used to evaluate the accuracy, precision, and suitability of a wide variety of ocean color chlorophyll algorithms for use by SeaWiFS (Sea-viewing Wide Field-of-view Sensor). The radiance-chlorophyll data were assembled from various sources during the SeaWiFS Bio-optical Algorithm Mini-Workshop (SeaBAM) and is composed of 919 stations encompassing chlorophyll concentrations between 0.019 and 32.79 μg L-1. Most of the observations are from Case I nonpolar waters, and ~20 observations are from more turbid coastal waters. A variety of statistical and graphical criteria were used to evaluate the performances of 2 semianalytic and 15 empirical chlorophyll/pigment algorithms subjected to the SeaBAM data. The empirical algorithms generally performed better than the semianalytic. Cubic polynomial formulations were generally superior to other kinds of equations. Empirical algorithms with increasing complexity (number of coefficients and wavebands), were calibrated to the SeaBAM data, and evaluated to illustrate the relative merits of different formulations. The ocean chlorophyll 2 algorithm (OC2), a modified cubic polynomial (MCP) function which uses Rrs490/Rrs555, well simulates the sigmoidal pattern evident between log-transformed radiance ratios and chlorophyll, and has been chosen as the at-launch SeaWiFS operational chlorophyll a algorithm. Improved performance was obtained using the ocean chlorophyll 4 algorithm (OC4), a four-band (443, 490, 510, 555 nm), maximum band ratio formulation. This maximum band ratio (MBR) is a new approach in empirical ocean color algorithms and has the potential advantage of maintaining the highest possible satellite sensor signal: noise ratio over a 3-orders-of-magnitude range in chlorophyll concentration.
A simple and typical typhoon process was constructed according to the primary feature of the SSTA caused by Typhoon in the Yellow Sea and the Bohai Sea.In this paper, an off-shore SSTA numerical forecasting model was employed to simulate the SST during a typhoon process in this area to further quantitatively analyze the cause of SSTA in summer. The SST changes caused by different possible factors in typhoon center and its adjacent points were given as well. The test showed that in the region disturbed by typhoon, coolwater pumping was the main cause of SST’s great decrease,wind entrainment played a second role; the effect of vaporing latent heat could not be ignored. A symmetry temperature decease effect(stronger to the right) and the phenomena of surfacewarm waters outward transportation and downwelling at the edge caused by typhoon w as clearly shown in the test. In addition, some key problems about the model are discussed and some aspects in which the model needs to be improved are mentioned in the third section.
Increased occurrence of more intense tropical storms intruding further poleward has been foreshadowed as one of the potential consequences of global warming. This scenario is based almost entirely on the general circulation model predictions of warmer sea surface temperature (SST) with increasing levels of atmospheric C02 and some theories of tropical cyclone intensification that support the notion of more intense systems with warmer SST. Whether storms are able to achieve this theoretically determined more intense state depends on whether the temperature of the underlying water is the dominant factor in tropical cyclone intensification. An examination of the historical data record in a number of ocean basins is used to identify the relative importance of SST in the tropical cyclone intensification process. The results reveal that SST alone is an inadequate predictor of tropical cyclone intensity. Other factors known to affect tropical cyclone frequency and intensity are discussed.
Ocean color properties can be quantified by the relationship between the band ratios of the sensor on the ocean color satellites and the measured field ocean color parameters, A tool to determine the abundance of primary organism using the observed ocean color properties from satellite is presented. Coincident to ocean color satellite passes over the Korean waters, the research vessels were deployed to survey the East Sea, the South Sea and the West Sea around the Korean waters, We have been able to have more than 101) data sets containing coincident in situ chlorophyll a and the estimated chlorophyll a derived from SeaWiFS (Sea-viewing Wide Field-of-view Sensor) from february, 1999 to October, 2001. We were able to develop three proper regional algorithms for the East Sea, the South Sea and the West Sea of the Korean peninsula to estimate chlorophyll a, and set up regional algorithms to quantify the suspended solid in the southern sea of the Korean peninsula, Futhermore we were successful in finding out a simple way of estimating chlorophyll a in the turbid water (Case 2 water) using the relationship between in situ chlorophyll a and the estimated chlorophyll a from the processed level 2 data, using the NASA's global algorithm.
A brief outline of the basic concepts of cloud filtering and atmospheric attenuation corrections used in the Multi-channel Sea Surface Temperature (MCSST) method is given. The operational MCSST procedures and products are described in detail. The comparative performance of AVHRR-based MCSST'S is discussed via the use of the results of the JPL Satellite-Derived Sea Surface Temperature workshops. For the four data periods there is surprisingly good correspondence in the sign and location of the major monthly mean SST anomaly features derived from MCSST's and those from a screened set of ship-based SST's. With the partial exception of the one data period severely affected in some areas by volcanic aerosol from El Chichon eruptions, global statistical measures of the MCSST anomalies relative to the the ship data are as follows: biases, 0.3–0.4°C (MCSST lower than ship); standard deviations, 0.5–0.6°C; and cross-correlations, +0.3 to +0.7. A refined technique in use with NOAA 9 data in 1985 has yielded consistent biases and rms differences near −0.1°C and 0.5°C, respectively.
Tropical cyclones rank with earthquakes as the major geophysical causes of loss of life and property. It is therefore of practical as well as scientific interest to estimate the changes in tropical cyclone frequency and intensity that might result from short term human-induced alterations of the climate. In this spirit a simple Carnot cycle model is used to estimate the maximum intensity of tropical cyclones under the somewhat warmer conditions expected to result from increased atmospheric CO2 content. Estimates based on August mean conditions over the tropical oceans predicted by a general circulation model with twice the present CO2 content yield a 40-50% increase in the destructive potential of hurricanes.
This study looks at the quantitative relationships between Ekman transport, longshore currents, surface productivity, and nutrient concentrations in coastal upwelling zones. Simple mass balance models of idealized coastal upwelling are presented and chemical data bases from well-studied modern oceanographic settings are then used to constrain the results of the mass balance models. Questions addressed by the author include the following: Are the relationships between productivity. Ekman transport, and nutrient flux consistent between upwelling zones in widely different settings Can the longshore model proposed by Redfield et al in 1963 be validated and used to explain the development of oxygen depletion and nutrient enrichment in water over continental shelves What implications might these models have for upwelling systems in the geologic past. 46 refs., 11 figs., 2 tabs.
A remarkable sea surface cooling event was observed in the north western Pacific off Japan coast, which is known as the Tohoku Area, by using well-calibrated satellite sea surface temperature images, when typhoons T8914 and T8915 passed over the Tohoku Area in August 1989. The sea surface cooling maximum reached up to 9°C, which is much larger than that reported in the previous studies. The corresponding hydrographic data show that the sea surface cooling state is closely related with the ocean structure in the Tohoku Area; the larger sea surface cooling occurs in the Oyashio area. The numerical experiments taking account of the ocean structure show that the surface cooling maximum is 3-4 times larger in case of the Oyashio profile than that of the Kuroshio profile and clarify the mechanism of the sea surface cooling.