• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.253-256
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• 2006

When the background tropospheric ozone column over the Pacific Ocean is subtracted from the latitudinal total ozone distribution, the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the T-P method. It suggests that the CCD method can be replaced by the simple T-P method. However, the tropical Atlantic paradox exists in the results of both the CCD and T-P methods during the northern burning season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and T-P methods by using the SAGE measurements (e.g. TSA method) and the SHADOZ ozonesoundings (e.g. T-S method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the T-SA and T-S methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and T-P methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.

• 대한원격탐사학회지
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• 제22권1호
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• pp.1-10
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• 2006

During the northern burning season, biomass burning is found north of the equator, while satellite estimates from the residual-type method such as the CCD method show higher ozone south of the equator. This discrepancy is called the tropical Atlantic paradox (Thompson et ai., 2000). We use satellite and ground-based measurements to investigate the paradox. When the background tropospheric ozone over the Pacific Ocean from TOMS measurements is subtracted from the latitudinal total ozone distribution (e.g. TOMS-Pacific method), the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD method. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the TOMS-Pacific method. It suggests that the complicated CCD method can be replaced by the simple TOMS-Pacific method. However, the tropical Atlantic paradox exists in the results of both the CCD and TOMS-Pacific methods during the northern buming season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and TOMS-Pacific methods by using the SAGE measurements (e.g. TOMS-SAGE method) and the SHADOZ ozonesoundings (e.g. TOMS-Sonde method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the TOMS-SAGE and TOMS-Sonde methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and TOMS-Pacific methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.366-369
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• 2005

A persistent maximum over the southern tropical Atlantic in the latitudinal tropospheric ozone distribution from the CCD method is seen in the latitudinal tropospheric ozone distribution from the TOMS-Pacific method. The tropical Atlantic paradox exists in the results of both the CCD and TOMS-Pacific methods. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the TOMS-SAGE and TOMS-Sonde methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and TOMS-Pacific methods.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E2호
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• pp.85-95
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• 2002

Hydrogen peroxide and methyl hydroperoxide were measured over the northwestern Pacific Ocean during NASA's PEM (Pacific Exploratory Mission) -West. The first experiment (PEM -West A) was conducted in the fall of 1991 and PEM-West B in the early spring of 1994. Hydroperoxide data were obtained on board the NASA DC -8 aircraft through the entire depth of the troposphere. Average concentrations of both H$_2$O$_2$and CH$_3$OOH were higher during PEM -West A than B. The seasonal difference in hydroperoxide distribution was determined by the degree of photochemical activities and the strength and location of jetstream, which led to extensive and rapid continental outflow during the PEM-West B. While for H$_2$O$_2$distribution, a longitudinal gradient was more apparent than a latitudinal gradient, it was opposite for the CH$_3$OOH distribution. The longitudinal gradient indicates the proximity to the anthropogenic sources from the Asian continent, but the latitudinal gradient reflects photochemical activity. During PEM -West B, the ratio of C$_2$H$_2$/CO, a tracer for continental emission was raised and high concentrations of H$_2$O$_2$were associated with high ratios. The flux of hydroperoxide toward the North Pacific was also enhanced in the early spring. The eastward fluxes of H$_2$O$_2$ were 9% and 17% of the average photochemical production over the Pacific Basin between 140°E and 130°W during PEM-West A and B, respectively. For CH$_3$OOH, these ratios were 8% and 13%. Considering the lifetime of hydroperoxide and the rapid transport of pollutants, the export of hydroperoxide with other oxidants would have a significant influence on oxidant cycles over the North Pacific during winter/spring.

• Ocean and Polar Research
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• 제33권spc3호
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• pp.349-358
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• 2011

In order to ascertain latitudinal variation of lipid contents and compositions in copepods, we collected warm water copepod species (Euchaeta sp. and Pleuromamma spp.) from four different regions from low (sub-tropical) to mid (temperate) latitudes in the Northwest Pacific Ocean. Total lipid contents of Pleuromamma spp. were about 11 $ug{\cdot}ind^{-1}$ with little latitudinal variation, whereas Euchaeta sp. showed slightly higher lipid content (20 $ug{\cdot}ind^{-1}$) than Pleuromamma spp. with latitudinal gradient (low at subtropic and high at temperate). Wax esters, known as the major storage lipid classes, were found to be the dominant lipid classes (accounting for more than 35% of total lipids) in Euchaeta sp., whereas in Pleuromamma spp., phospholipids, known as cellular membrane components, were the dominant lipid classes. However, the exception was specimens from warm pool region exhibiting dominance in storage of lipids as a form of triacylglycerols. Among fatty acids, polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA : 22:6(n-3)) (about 35% of total fatty acids), were most abundant in Euchaeta sp., while saturated fatty acids (SAFA), specially hexadecanoic acid (16:0) (about 30% of total fatty acids), were most abundant in Pleuromamma spp.. Among the neutral fraction of lipids, phytol, originated from the side chain of chlorophyll, was found in all samples which generally indicate active copepods feeding on algae. While only trace amounts of short-chain fatty alcohols were found in Pleuromamma spp., significant amounts of fatty alcohols were found in Euchaeta sp.. Particularly, significant amounts of long chain monounsaturated fatty alcohols (20:1 and 22:1), generally found in cold water species, were found in Euchaeta sp. from low latitudes. The latitudinal variation of trophic lipid markers in these copepods could be significantly related with in-situ food availability and species-specific diet preference. The result of this study suggests that the lipid contents and compositions in copepods may not only indicate their nutritional condition and feeding ecology but also provide insight into species-specific living strategies under different environmental conditions (i.e. water temperature, food availability).

• 대기
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• 제26권4호
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• pp.665-672
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• 2016

In this study, we examine future changes in the Hadley cell (HC) strength using CMIP5 climate change simulations. The current study is an extension of a previous study by Seo et al. that used all 30 available models. Here, we select 18-23 well-performing models based on their significant internal sensitivity of the interannual HC strength variation to the latitudinal temperature gradient variation. The model projections along with simple scaling analysis show that the inter-model variability in the HC strength change is a result of the inter-model spread in the meridional temperature gradient across the subtropics for both DJF and JJA, not by the tropopause height or gross static stability change. The HC strength is expected to weaken significantly during DJF, while little change is expected in the JJA HC strength. Compared to the calculations with all model members, selected model statistics increase the linear correlation between the changes in HC strength and meridional temperature gradient by 13~23%, confirming the robust sensitivity of the HC strength to the meridional temperature gradient. Two scaling equations for the selected models predict changes in HC strength better than all-member predictions. In particular, the prediction improvement in DJF is as high as 30%. The simple scaling relations successfully predict both the ensemble-mean changes and model-to-model variations in the HC strength for both seasons.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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• pp.26.3-27
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• 2011

Formation of a steep plasma density gradient in the middle-latitude ionosphere during geomagnetic storms and the latitudinal migration of its location depending on the storm phase are suggested to be associated with the ionospheric signature of the plasmapause. We test this idea by using the satellite and ground observation data during the 11 April 2001 storm. The locations of the steep plasma density gradient identified by TOPEX/Poseidon (2001 LT) and DMSP (1800 and 2130 LT) satellites coincide with the ionospheric footprints of the plasmapause identified by the IMAGE satellite. This observation may support the dependence of the middle-latitude plasma density gradient location on the plasmapause motion, but does not explain why the steep density gradient whose morphology is largely different from the morphology of the middle-latitude ionization trough during quiet period is formed in association with the plasmapause. The ionospheric disturbances in the total electron content (TEC) maps shows that the steep TEC gradient is formed at the boundary of the positive ionospheric storm in low-middle latitudes and the negative ionospheric storm in middle-high latitudes. We interpret that the thermospheric neutral composition disturbance in the dayside is confined within the middle-high latitude ionospheric convection zone. The neutral composition latitudes and, therefore, the locations of the steep plasma density gradient coincide with the footprints of the plasmapause. The TEC maps show that the appearance of the steep plasma density gradient in the pre-midnight sector during the recovery phase is related to the co-rotation of the gradient that is created during the main phase.

• 한국대기환경학회지
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• 제27권6호
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• pp.650-662
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• 2011

The statistical tools such as empirical orthogonal function (EOF), and singular value decomposition (SVD) have been applied to analyze the characteristic of air pollutant over southeast Asia as well as to evaluate Zimeke's tropospheric column ozone (ZTO) determined by tropospheric residual method. In this study, we found that the EOF and SVD analyses are useful methods to extract the most significant temporal and spatial pattern from enormous amounts of satellite data. The EOF analyses with OMI $NO_2$ and OMI HCHO over southeast Asia revealed that the spatial pattern showed high correlation with fire count (r=0.8) and the EOF analysis of CO (r=0.7). This suggests that biomass burning influences a major seasonal variability on $NO_2$ and HCHO over this region. The EOF analysis of ZTO has indicated that the location of maximum ZTO was considerably shifted westward from the location of maximum of fire count and maximum month of ZTO occurred a month later than maximum month (March) of $NO_2$, HCHO and CO. For further analyses, we have performed the SVD analyses between ZTO and ozone precursor to examine their correlation and to check temporal and spatial consistency between two variables. The spatial pattern of ZTO showed latitudinal gradient that could result from latitudinal gradient of stratospheric ozone and temporal maximum of ZTO in March appears to be associated with stratospheric ozone variability that shows maximum in March. These results suggest that there are some sources of error in the tropospheric residual method associated with cloud height error, low efficiency of tropospheric ozone, and low accuracy in lower stratospheric ozone.

• International Journal of Industrial Entomology and Biomaterials
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• 제48권1호
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• pp.48-58
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• 2024

Reports of a global decline in pollinator populations, especially mason bees, have raised concerns regarding the maintenance of pollination interactions. Although addressing local factors causing bee decline is a potential mitigation strategy at the landscape scale, regional rates and high-latitude threats to bee diversity are unclear. We investigated the distribution of mason bees (Osmia. spp. (O. pedicornis, O. corniforns, O. taurus, and O. satoi) and measured species richness and species ratios at regional, latitudinal, and altitudinal scales. We examined the association between bee species richness and three putative environmental conditions: high-low, altitude-dependent, and latitude-dependent. The species richness of the O. pedicornis bee was the highest and it was found between latitudes 35° and 37°, and at 500-600 m in both the northern and southern hemispheres, showing an inverse latitudinal gradient of bee species richness in South Korea. Mason bee species richness and global climate are important predictors of flowering plant diversity. Climate change threatens bee and vascular plant diversity; however, the overlap between bee abundance and plant diversity can be improved by employing suitable conservation strategies.

• 생명과학회지
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• 제23권6호
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• pp.728-735
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• 2013

질경이(Plantago asiatica)는 주로 동아시아에 분포하는 풍매화 식물이다. 전분 젤 전기영동으로 이 종의 18개 집단에 대한 알로자임 다양성과 집단구조를 평가하였다. 비록 질경이 집단은 작고 격리되어 있지만, 높은 유전적 다양성을 가지고 있었다. 평균 다형성을 나타내는 유전자좌위의 수는 57.1%였고, 대립유전자좌위당 유전자수는 2.07이였으며, 18개 집단에 대한 이형접합성은 0.201이였다. 풍매화, 혼합적 생식교배계, 큰 집단 크기, 집단 간 높은 유전자 이동, 다산의 특성이 집단 내 유전적 다양성을 설명할 수 있다. 유전적 다양성은 위도와 관련이 있었는데 질경이 집단은 북위 $35^{\circ}3^{\prime}$를 초과하면 유전적 다양성은 현저하게 감소하였다. 반면에 유전적 다양성에 대한 경도 구배는 나타나지 않았다.