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Circulation Pattern Controls of Summer Temperature Anomalies in Southern Africa

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Advances in Atmospheric Sciences 2024年第2期41卷 341-354页

作者： Chibuike Chiedozie IBEBUCHI Cameron C.LEE Department of geography Kent State UniversityKentOhio 44242USA ClimRISE Lab Kent State UniversityKentOhio 44242USA

This study investigates the relationship between circulation patterns and austral summer temperature anomalies in southern Africa. The results show that the formation of continental lows tends to increase the thickness of the lower atmosphere. Further, the distinct variabilities of high and low pressure under the circulation types, influence air mass advection from the adjacent oceans, as well as atmospheric stability over land. Stronger anticyclonic circulation at the western branch of the Mascarene high-pressure system enhances the low-level cold air advection by southeast winds,decreases the thickness, and lowers the temperature over a majority of the land in southern Africa. Conversely, a weaker Mascarene High, coupled with enhanced cyclonic activity in the southwest Indian Ocean increases low-level warm air advection and increases temperature anomalies over vast regions in southern Africa. The ridging of a closed South Atlantic anticyclone at the southern coast of southern Africa results in colder temperatures near the tip of southern Africa due to enhanced low-level cold air advection by southeast winds. However, when the ridge is weak and westerly winds dominate the southern coast of southern Africa, these areas experience temperature increases. The northward track of the Southern Hemisphere mid-latitude cyclone, which can be linked to the negative Southern Annular Mode, reduces the temperature in the southwestern part of southern Africa. Also, during the analysis period, El Ni?o was associated with temperature increases over the central parts of southern Africa;while the positive Indian Ocean dipole was linked to a temperature increase over the northeastern, northwestern, and southwestern parts of southern Africa.

关键词： temperature circulation types Subtropical Indian Ocean dipole Southern Annular Mode El Ni?o Indian Ocean dipole Mascarene High South Atlantic anticyclone

Local Variability in Temperature, Humidity and Radiation in the BaekduDaegan Mountain Protected Area of Korea

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Journal of Mountain Science 2012年第5期9卷 613-627页

作者： CHAE Heemun LEE Hyunju LEE Sangsin CHEONG Yukyong UM Gijeung MARK Bryan PATRICK Nathan Department of Forest Environment Protection College of Forest and Environmental ScienceKangwon National University Department of geography and Byrd Polar Research Center Ohio State University

A novel embedded sensor network records changes in key climatic-environmental variables over a range of altitude in the BaekduDaegan Mountain （BDM） of Gangwon Province in Korea, a protected mountain region with unique biodiversity undergoing climate change research. The investigated area is subdivided into three horizontal north-south study areas. Three variables, temperature （T, °C）, relative humidity （RH, %）, and light intensity （LI, lumens m-2, or lux, lx）, have been continuously measured at hourly intervals from June, 2olo to September, 2011 using HOBO H8 devices at lO fixed study sites. These hourly observations are aggregated to monthly, seasonal and annual mean values, and results are summarized to inaugurate a long-term climate change investigation. A region wide T difference in accordance with altitude, or lapse rate, over the interval is calculated as o.4°C l00 m-1. T lapse rates change seasonally, with winter lapse rates being greater than those of summer. RH is elevated in summer compared to other seasons. LI within forestland is lower during summer and higher during other seasons. The obtained results could closely relate to the vegetation type and structure and the terrain state since data loggers were located in forestland.

关键词： Embedded sensors Temperature lapserates Relative humidity Light intensity Forest Climate change BaekduDaegan Mountain

Spatiotemporal reflectance blending in a wetland environment

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International Journal of Digital Earth 2015年第5期8卷 364-382页

作者： Ryo Michishita Lifan Chen Jin Chen Xiaolin Zhu Bing Xu College of Global Change and Earth System Science Beijing Normal UniversityBeijingChina Department of geography Ohio State UniversityColumbusOHUSA School of Environment Tsinghua UniversityBeijingChina Department of geography University of UtahSalt Lake CityUTUSA

To understand the mechanism of wetland cover change with both moderate spatial resolution and high temporal frequency,this research evaluates the applicability of a spatiotemporal reflectance blending model in the Poyang Lake area,China,using 9 time-series Landsat-5 Thematic Mapper images and 18 time-series Terra Moderate Resolution Imaging Spectroradiometer images acquired between July 2004 and November *** customized blending model was developed based on the enhanced spatial and temporal adaptive reflectance fusion model(ESTARFM).Reflectance of the moderate-resolution image pixels on the target dates can be predicted more accurately by the proposed customized model than the original *** level on the input image acquisition dates strongly affected the accuracy of the blended *** was found that either of the image sets used as prior or posterior inputs are required when the difference of water level between the prior or posterior date and target date at Poyang Hydrological Station is<2.68 m to achieve blending accuracy with a mean average absolute difference of 4%between the observed and blended reflectance in all spectral bands.

关键词： time-series blending model spatial-temporal reflectance multi-sensor Landsat TM MODIS

Spatiotemporal Dynamics of a Páramo Ecosystem in the Northern Ecuadorian Andes 1988-2007

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Journal of Mountain Science 2014年第3期11卷 708-716页

作者： Oliver WIGMORE Jay GAO School of Environment University of Auckland Private Bag 92019 Auckland New Zealand Department of geography The Ohio State University 1036 Derby Hall 154 N Oval Mall Columbus Ohio 43210 USA Byrd Polar Research Center The Ohio State University 108 Scott Hall 1090 Carmack Road Ohio 43210 USA School of Environment University of Auckland Private Bag 92019 Auckland New Zealand

Paramo is a term used to describe tropical alpine vegetation between the continuous timberline and the snow line in tbe Northern Andes. Paramo environments provide important species habitat and ecosystem services. Changes in spatial extent of the paramo ecosystem at Pambamarca in the Central Cordillera of the northern Ecuadorian Andes were analysed using multi-temporal Landsat TM/ETM＋ satellite data. The region suffered a loss of 1826.6 ha or 20% of the total area at a rate of 100 ha/annum during 1988-2007 period. It is found that permanent paramo cover decreased from 8350 ha in 1988 to 5864 ha in 2007 at a fairly constant rate （R^2=0.94）. This loss is attributed to expansion of commercial agriculture and floriculture in the valleys coupled with increased population pressure. Land at higher elevations has been cleared for small scale agriculture. Loss of the paramo ecosystem will exert a number of negative impacts on ecosystem services and livelihoods of the local population at Pambamarca.

关键词： Paramo ecosystem Change analysis Remote sensing Andes

No-till and conservation agriculture in the United states:An example from the David Brandt farm,Carroll,ohio

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International Soil and Water Conservation Research 2014年第1期2卷 97-107页

作者： R.Islam R.Reeder Soil Water and Bioenergy ResourcesOhio State University South CentersOH Agricultural and Biological Engineering dept. Ohio State University

No-till(NT)farming(conservation agriculture)began in the US in the *** state of ohio has a university research location that began no-till research in 1962.A few innovative ohio farmers,including NT pioneers David Brandt and Bill Richards,were early adopters of the new conservation ***,no-till was most successful on sloping,well drained soils,then with improvements to the system,including cover crops,it became more widely adopted on all soil *** Brandt was an enthusiastic learner and teacher of no-till practices,working with chemical company representatives and Cooperative Extension Specialists to demonstrate the *** Brandt’s cooperation with ohio state university researchers continues to provide a valuable site for studying the long term changes in soil health and ecosystem *** showed that total microbial biomass as one of the soil biological health indicators significantly increased with an associated decrease in carbon(C)loss under NT compared with conventional tilled soil(CT).Under NT,there was significantly higher total C and total N compared to *** C,as a composite measure of soil health,significantly increased with *** cover crops,especially cover crop cocktail mixes,were used,NT substantially improved soil ***-term NT with cover crop cocktail mixes significantly increased the soil aggregate stability,compared with *** overall rate of C sequestration by NT suggested that the soils on the Brandt farm act as a consistent sink of atmospheric CO2 although this tends to level off after about 20 *** Brandt farm showed that crop yields are increased under long-term NT with cover crops *** suggested that starting with a cover crop when switching from CT to NT,is more likely to ensure success and to maintain economic crop *** early adopter,Bill Richards,from Circleville,ohio,also became a national leader and promoter of no-till *** served as head of the United Sta

关键词： Innovation Eco-farming Corn Soybeans Wheat Cover crops Carbon sequestration Soil organic matter Agroecosystems Carbon management index Farm bill Government policy

Spatiotemporal event detection: a review

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International Journal of Digital Earth 2020年第12期13卷 1339-1365页

作者： Manzhu Yu Myra Bambacus Guido Cervone Keith Clarke Daniel Duffy Qunying Huang Jing Li Wenwen Li Zhenlong Li Qian Liu Bernd Resch Jingchao Yang Chaowei Yang Department of geography Pennsylvania State UniversityUniversity ParkPAUSA NASA Goddard Space Flight Center NASA Goddard Space Flight CenterGreenbeltMDUSA Department of geography University of California-Santa BarbaraSanta BarbaraCAUSA Department of geography University of Wisconsin-MadisonMadisonWIUSA Department of geography and the Environment University of DenverDenverCOUSA School of Geographical Sciences and Urban Planning Arizona State UniversityTempeAZUSA Department of geography University of South CarolinaColumbiaSCUSA NSF Spatiotemporal Innovation Center&dept.of geography and GeoInformation Science George Mason UniversityFairfaxVAUSA Department of Geoinformatics University of SalzburgKapitelgasseSalzburgAustria Center for Geographic Analysis Harvard UniversityBostonMAUSA

The advancements of sensing technologies,including remote sensing,in situ sensing,social sensing,and health sensing,have tremendously improved our capability to observe and record natural and social phenomena,such as natural disasters,presidential elections,and infectious *** observations have provided an unprecedented opportunity to better understand and respond to the spatiotemporal dynamics of the environment,urban settings,health and disease propagation,business decisions,and crisis and *** event detection serves as a gateway to enable a better understanding by detecting events that represent the abnormal status of relevant *** paper reviews the literature for different sensing capabilities,spatiotemporal event extraction methods,and categories of applications for the detected *** novelty of this review is to revisit the definition and requirements of event detection and to layout the overall workflow(from sensing and event extraction methods to the operations and decision-supporting processes based on the extracted events)as an agenda for future event detection *** is presented on the current challenges to this research agenda,and future directions are discussed for conducting spatiotemporal event detection in the era of big data,advanced sensing,and artificial intelligence.

关键词： GeoAI geography and geoscience human dynamics digital earth computational challenges cloud computing internet of things

Reconstructing rice phenology curves with frequency-based analysis and multi-temporal NDVI in double-cropping area in Jiangsu, China

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Frontiers of Earth Science 2016年第2期10卷 292-302页

作者： Hongshuo WANG Hui LIN Darla K. MUNROE Xiaodong ZHANG Pengfei LIU College of Information and Electrical Engineering China Agricultural University Beijing 100083 China Institute of Space and Earth Information Science The Chinese University of Hong Kong Hong Kong China Department of geography and Resource Management The Chinese University of Hong Kong Hong Kong China Department of geography The Ohio State University Columbus OH 43210 USA School of Mathematics and Statistics Jiangsu Normal University Xuzhou 221116 China

Crop phenology retrieval in the double-crop- ping area of China is of great significance in crop yield estimation and water management under the influences of global change. In this study, rice phenology in Jiangsu Province, China was extracted from multi-temporal MODIS NDVI using frequency-based analysis. Pure MODIS pixels of rice were selected with the help of TM images. Discrete Fourier Transformation （DFT）, Discrete Wavelet Transformation （DWT）, and Empirical Mode Decomposition （EMD） were performed to decompose time series into components of different frequencies. Rice phenology in the double-cropping area is mainly located on the last 2 IMFs of EMD and the first 2-3 frequencies of DFT and DWT. Compared with DFT and DWT, EMD is limited to fewer frequencies. Multi-temporal MODIS NDVI data combined with frequency-based analysis can retrieve rice phenology dates with on average 79% valid estimates. The sorting result for effective estimations from different methods is DWT （85%）〉 EMD （80%）〉 DFT （74%）. Planting date （88%） is easier to estimate than harvesting date （70%）. Rice planting date is easily affected by the former cropping mode within the same year in a double-cropping region. This study sheds light on under- standing crop phenology dynamics in the frequency domain of multi-temporal MODIS data.

关键词： discrete Fourier transformation discretewavelet transformation empirical mode decomposition,rice phenology double-cropping

Development and Applications of Dome A-DEM in Antarctic Ice Sheet

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Chinese Geographical Science 2007年第2期17卷 160-165页

作者： LIU Jiying WEN Jiahong WANG Yafeng WANG Weili Beata M CATHSO Kenneth CJEZEK Department of geography Shanghai Normal University Shanghai 200234 China SGT NASA Goddard Space Flight Center Code 614.1 Greenbelt MD 20771 USA Byrd Polar Research Center the Ohio State University Columbus OH43210 USA

Dome A, the highest dome of East Antarctic Ice Sheet, is being an area focused by international Antarctic community after Chinese Antarctic Expedition finally reached there in 2005, and with the ongoing International Polar Year （IPY） during August 2007. In this paper two data processing methods are used together to generate two 100-m cell size digital elevation models （DEMs） of the Dome A region （Dome A-DEM） by using Cokriging method to interpolate the ICESat GLAS data, with Ihde-DEM as a constraint. It provides fundamental data to glaciological and geophysical investigation in this area. The Dome A-DEM was applied to determining the ice-sheet surface elevations and coordinates of the south and north summits, defining boundaries of basins and ice ftowlines, deducing subglacial topography, and mapping surface slope and aspect in Dome A region. The DEM shows there are two （north and south） summits in Dome A region. The coordinate and the surface elevation of the highest point （the north summit） are 80°21＇29.86＂S, 77°21＇50.29＂E and 4092.71±1.43m, respectively. The ice thickness and sub-ice bedrock elevation at north summit are 2420m and 1672m, respectively. Dome A region contains four drainage basins that meet together near the south summit. Ice ftowlines, slope and aspect in detail are also derived using the DEM.

关键词： Dome A ICESat GLAS Cokriging DEM Antarctica

Extreme Antarctic Cold of Late Winter 2023

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Advances in Atmospheric Sciences 2024年第10期41卷 1873-1880页

作者： Anastasia J.TOMANEK David E.MIKOLAJCZYK Matthew A.LAZZARA Stefano DI BATTISTA Minghu DING Mariana FONTOLAN LITELL David H.BROMWICH Taylor P.NORTON Linda M.KELLER Lee J.WELHOUSE Antarctic Meteorological Research and Data Center Space Science and Engineering CenterUniversity of Wisconsin-MadisonMadisonWisconsin 53706USA Department of Physical Sciences School of EngineeringScienceand MathematicsMadison Area Technical CollegeMadisonWisconsin 53704USA Meteogiornale via Paolo Diacono9Milano 20133Italy state Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Byrd Polar and Climate Research Center The Ohio State UniversityColumbusOhio 43210USA Department of geography The Ohio State UniversityColumbusOhio 43210USA

Extreme cold temperatures were observed in July and August 2023,coinciding with the WINFLY(winter fly-in)period of mid to late August into September 2023,meaning aircraft operations into McMurdo Station and Phoenix Airfield were adversely ***,with temperatures below−50℃,safe flight operation was not possible because of the risk of failing hydraulics and fuel turning to gel onboard the *** cold temperatures were measured across a broad area of the Antarctic,from East Antarctica toward the Ross Ice Shelf,and stretching across West Antarctica to the Antarctic Peninsula.A review of automatic weather station measurements and staffed station observations revealed a series of sites recording new record low *** separate cold phases were identified,each a few days in duration and occurring from mid-July to the end of August 2023.A brief analysis of 500-hPa geopotential height anomalies shows how the mid-tropospheric atmospheric environment evolves in relation to these extreme cold *** monthly 500-hPa geopotential height anomalies show strong negative anomalies in *** of composite geopotential height anomalies during each of the four cold phases suggests various factors leading to cold temperatures,including both southerly off-content flow and calm atmospheric *** the atmospheric environment that leads to such extreme cold temperatures can improve prediction of such events and benefit Antarctic operations and the study of Antarctic meteorology and climatology.

关键词： Antarctica extreme cold temperature automatic weather station networks