Zhang J.,Nanjing University of Information Science and Technology |
Zhang J.,CMA Technologies, Inc. |
Li L.,Nanjing University of Information Science and Technology |
Li L.,University Pierre and Marie Curie |
And 2 more authors.
International Journal of Climatology | Year: 2015
Summer rainfall in north-central China, accounted for 70% of the annual rainfall, is sensitive to anomalies in the East Asian summer monsoon (EASM) and westerlies due to lying in the EASM marginal belt. Summer rainfall and the durations and frequency of dry spells were investigated using daily rainfall data from 332 weather stations, the European Centre for Medium-range Weather Forecasting (ECMWF) re-analysis data and Climate Research Unit (CRU) surface temperature data. The results demonstrate that summer rainfall exhibits an 'early wetting later drying' pattern with a weak increasing in June and a dramatic decreasing trend in July and August (JA). Decreased rainfall in JA is associated with prolonged dry spells; the frequency and durations of dry spells exceeding 7 days increase, especially for dry spells exceeding 15 days. This increase in dry spell duration is positively correlated with a northward shift in planetary waves expressed by the 5700-gpm isoline at 500 hPa and the westerly jet at 200 hPa, which lead north-central China to close to the left of jet entrance and a positive vorticity convergence region on the high level, it is helpful to downward movements and less rainfall. The northward shift in planetary waves is affected by boundary forcing. Dramatic increases in temperature over the Tibetan Plateau (TP) result in a large temperature gradient and thermal contrast between the TP and mid-high latitude, and likely strengthening and widening the South Asian High (SAH) pattern and pressure gradient. These conditions contribute to the northward shift in planetary waves and prolonging dry spells. © 2015 Royal Meteorological Society.
Zhang F.,Chinese Academy of Meteorological Sciences |
Zhang F.,University of Chinese Academy of Sciences |
Zhou L.X.,Chinese Academy of Meteorological Sciences |
Novelli P.C.,National Oceanic and Atmospheric Administration |
And 9 more authors.
Atmospheric Chemistry and Physics | Year: 2011
Quasicontinuous measurements of carbon monoxide (CO) recorded over three years at Mount Waliguan (WLG), a global baseline station in remote western China, were examined using back trajectory analysis. The data include a revision to correct the working reference scale to the WMO2000 scale and corrections for drift in the reference gases. Between July 2004 and June 2007, CO exhibited large fluctuations and the 5 %, 50 % and 95 %-percentiles of relevant CO mixing ratios were 102 ppb, 126 ppb and 194 ppb. Approximately 50 % of all observed data were selected as CO background data using a mathematical procedure of robust local regression, with the remainder affected by regional-scale pollution. The monthly mean background CO mixing ratios showed a minimum in summer and a maximum in late winter, although all seasons were affected by short-term enhancements that exceeded background levels. The CO data were compared to values observed at the high alpine research station at Jungfraujoch, Switzerland. Smaller seasonal amplitudes were observed at WLG compared to the Jungfraujoch due to lower winter and spring CO levels, however, episodic enhancements of polluted air were greater at WLG. The air parcels arriving at WLG came predominately from the west, except in summer when advection from the east and southeast prevailed. Transport from the east or southeast typically brought polluted air to the site, having passed over populated urban areas upwind. A large number of elevated CO mixing ratios could also be associated with advection from the northwest of WLG via the central Xinjiang Uygur Autonomous Region (XUAR) and the Ge'ermu urban area where growing industrial activities as well as crops residue burning provide sources of CO. Air masses passing over northwestern Gansu were associated with relatively high CO values suggesting an anthropogenic influence, which was likely due to anthropogenic emissions from northwestern China (based on back-trajectory and potential source contribution analysis and on the INTEX-B: intercontinental Chemical Transport Experiment-Phase B). Background conditions were observed most frequently in air parcels from remote Tibet west of WLG. The probability that air parcels pass over regions of clean or polluted regions was further identified using potential source contribution function (PSCF) analysis. © 2011 Author(s).
Yu S.,The Institute of Plateau Meteorology |
Gao W.,CMA Technologies, Inc. |
Peng J.,The Institute of Plateau Meteorology |
Xiao Y.,Sichuan Provincial Meteorological Observatory
Journal of Meteorological Research | Year: 2014
By using the twice-daily atmospheric observation data from 1998 to 2012, station rainfall data, Tropical Rainfall Measure Mission (TRMM) data, as well as the plateau vortex and shear line year book, characteristics of the sustained departure plateau vortexes (SDPVs) are analyzed. Some new useful observational facts and understanding are obtained about the SDPV activities. The following results are obtained. (1) The active period of SDPVs is from June to August, most in July, unlike that of the unsustained departure plateau vortexes (UDPVs), which have same occurrence frequencies in the three summer months. (2) The SDPVs, generated mainly in the Qumalai neighborhood and situated in a sheared surrounding, move eastward or northeastward, while the UDPVs are mainly led by the upper-level trough, and move eastward or southeastward. (3) The SDPVs influence wide areas of China, even far to the Korean Peninsula, Japan, and Vietnam. (4) The SDPVs change their intensities and properties on the way to the east. Most of them become stronger and produce downpour or sustained regional rainstorms to the south of Yellow River. (5) The longer the SDPV sustains, the more baroclinity it has. (6) When an SDPV moves into the sea, its central pressure descends and rainfall increases in all probability. (7) An SDPV might spin over the bend of the Yellow River when there exists a tropical cyclone in the East China Sea. It could also move oppositely to a landed tropical low pressure originated from the sea to the east of Taiwan or from the South China Sea. © The Chinese Meteorological Society and Springer-Verlag Berlin Heidelberg 2014.
Zhang L.,Nanjing University of Information Science and Technology |
Ren G.-Y.,National Climate Center |
Ren Y.-Y.,National Climate Center |
Zhang A.-Y.,CMA Technologies, Inc. |
And 2 more authors.
Theoretical and Applied Climatology | Year: 2014
Daily minimum temperature (Tmin) and maximum temperature (Tmax) data of Huairou station in Beijing from 1960 to 2008 are examined and adjusted for inhomogeneities by applying the data of two nearby reference stations. Urban effects on the linear trends of the original and adjusted temperature series are estimated and compared. Results show that relocations of station cause obvious discontinuities in the data series, and one of the discontinuities for Tmin are highly significant when the station was moved from downtown to suburb in 1996. The daily Tmin and Tmax data are adjusted for the inhomogeneities. The mean annual Tmin and Tmax at Huairou station drop by 1.377°C and 0.271°C respectively after homogenization. The adjustments for Tmin are larger than those for Tmax, especially in winter, and the seasonal differences of the adjustments are generally more obvious for Tmin than for Tmax. Urban effects on annual mean Tmin and Tmax trends are -0.004°C/10 year and -0.035°C/10 year respectively for the original data, but they increase to 0.388°C/10 year and 0.096°C/10 year respectively for the adjusted data. The increase is more significant for the annual mean Tmin series. Urban contributions to the overall trends of annual mean Tmin and Tmax reach 100% and 28.8% respectively for the adjusted data. Our analysis shows that data homogenization for the stations moved from downtowns to suburbs can lead to a significant overestimate of rising trends of surface air temperature, and this necessitates a careful evaluation and adjustment for urban biases before the data are applied in analyses of local and regional climate change. © 2013 The Author(s).
Wang Y.,CMA Technologies, Inc. |
Wang Y.,National Climate Center |
Yan F.,Chinese Academy of Forestry
Journal of Natural Disasters | Year: 2014
Based on the NCEP reanalysis data and the monthly precipitation data of 723 meteorological stations, the characteristics of the rainfall anomalies in China in Nov. 2011 and the related large-scale atmosphere circulation over the Eurasia region were analyzed, and the effects of the La Nina event and Arctic oscillation on anomalies of rainfall and atmosphere circulation in China were studied. Results show that, affected by the La Nina event and the Arctic oscillation, atmosphere circulation over the Eurasia region appeared abnormal in November 2011. On one hand, the Indian Burma trough deepens and the west Pacific subtropical high extends westward, which strengthenes the transportation of the wet-warm air from the Bay of Bengal to the South China Sea and the west Pacific Ocean to Inland of China. On the other hand, the strengthening of the subtropical westerly jet and the jet axis fracture make the regions from the northeastern West China to North China and coastal areas of South China lie in the high-level divergence regions of jet south side, which strengthens the divergence of upper air and convergence of lower air in these regions. Due to the enough vapor conditions combined with a better uplifting conditions of vapor, the precipitation is more than normal in these two regions.
Desai B.M.,Indian Institute of Management |
D'Souza E.,CMA Technologies, Inc. |
Mellor J.W.,International Food Policy Research Institute |
Sharma V.P.,CMA Technologies, Inc. |
Tamboli P.,University of Maryland College Park
Economic and Political Weekly | Year: 2011
For 40 years, India's agricultural growth rate has averaged less than one-third of the government's modest target of 4%. The sector's performance has been about the same before and after the economic reforms in the early 1990s. The reforms that brought a dramatic acceleration of growth in urban sectors have essentially had no effect on agriculture. Slow agricultural growth has had ill-effects on food security, food price inflation and poverty reduction because of the inadequate level and composition of public expenditure. Agricultural education, research, extension and a wide range of ancillary public institutions have also suffered. Agricultural growth always demands massive public goods provision and that in turn requires a radical reorientation of central, state and district government activities. This paper advocates a new integrated, technology-led strategy to pull out of what looks like, a vicious circle that agriculture is now caught in.
Pan X.,Texas A&M University-Kingsville |
Shen D.,CMA Technologies, Inc. |
Dong X.,North Dakota State University |
Patton B.,North Dakota State University
Disaster Advances | Year: 2011
In the context of climate change, there is potential for a higher frequency of natural disasters. Here a linear regression analysis is employed to link the relationship between the natural disaster occurrence and average global temperature from 1980 to 2010. The results indicate that epidemic, extreme temperature, flood and storm events are strongly affected by climate. If the average global temperature increases by 1 °C, the occurrence of epidemic, extreme temperature, flood and storm would increase by 101, 42, 268 and 95 occurrences per year respectively.
Zhang H.-W.,CMA Technologies, Inc. |
Chen H.-L.,CMA Technologies, Inc.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2015
The vegetation coverage is one of the important factors that restrict the accuracy of remote sensing retrieval of soil moisture. In order to effectively improve the accuracy of the remote sensing retrieval of soil moisture and to reduce the impact of vegetation coverage variation on the retrieval accuracy, the Leaf Area Index (LAI) is introduced to the Normalized Difference Water Index (NDWI) to greatly improve the accuracy of the soil moisture retrieval. In its application on the regional drought monitoring, the paper uses the relative LAI from two places which locate in the north and south of Henan Province respectively (Xin Xiang and Zhu Ma Dian) as indicators. It uses the days after turned-green stage to conduct difference value correction on the Relative Leaf Area Index (RLAL) of the entire province, so as to acquire the distribution of RLAI of the province's wheat producing area. After this, the local remote sensing NDWI will be Modified (MNDWI = NDWI × RLAI) to acquire the soil moisture distribution status of the entire province's wheat producing area. The result shows that, the Modified Normalized Difference Water Index of LAI which based on the days after turned-green stage can improve the real time retrieval accuracy of soil moisture under different vegetation coverage.
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 99.98K | Year: 2015
The Hellfire air-to-ground missile is a combat-proven system that can be launched from multiple platforms with precision strike lethality. The benefits of this project are to increase the effectiveness and utility of the Hellfire missile by increasing the range which is achieved through the reduction of the fly-away aerodynamic drag of the missile after launch. This reduction in drag is achieved by the conversion of the current shotgun connecter with a new low profile connector and adapter. The technical objective of this Phase I SBIR study is to select a design alternative to the existing Hellfire shotgun connector that will mate to any unmodified launch and will to maintain the existing shotgun missile to launcher mechanical and electrical interfaces while also mating to the Hellfire Guidance Section Housing. The existing shotgun connector on the Guidance Section Housing is a significant drag feature of the Hellfire missile. By selecting and incorporating a new low profile connector the Guidance Section Housing can be modified to reduce its profile that results in a fly-away configuration that has decreased aerodynamic drag. The adapter will be securely retained by launcher after the missile has been launched.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.94K | Year: 2014
The government has identified the need for scientific measurements of the stimuli produced on a human surrogate for human effects testing of different non-lethal weapon technologies including blunt trauma, monochromatic and broadband light, blast over-pressure thermal energy, electrical current, chemical irritants and electromagnetic radiation. Given this wide variety of stimuli, CMA Technologies opted to team with the world"s leading manufacturer of Anthropomorphic Test Devices (ATD), Humanetics Innovative Solutions, to use a mature human-surrogate with proven sensors, to include those for blunt trauma, thermal measurement and blast-overpressure, as a starting point for the design. CMA Technologies is proposing a disciplined systems engineering approach to thoroughly define measurement requirements and to select commercial-off-the shelf sensors that augment the existing system to meet the rest of the government"s measurement needs. CMA is proposing a modular approach where different sensors can be mounted on the ATD as needed for the measurement scenario. In some instances, a different ATD limb or attachment may be needed to use specific sensors while in other instances a sensor can be mounted on the ATD to obtain the necessary measurement. The data acquisition system will have"plug-and-play"functionality designed to incorporate any sensor with minimal user reconfiguration required.