Time filter

Source Type

Yu G.-k.,Jiangsu Meteorological Bureau | Luo Y.,Anhui Meteorological Bureau | Gao P.,Jiangsu Meteorological Bureau | Zhao X.-y.,Nanjing University of Information Science and Technology | And 2 more authors.
Chinese Journal of Ecology | Year: 2012

Based on the meteorological and social-economic statistical data in 1982-2009, and by using agricultural economy-climate model (C-D-C model), this paper analyzed the meteorological sensitivity of the agricultural economy in three representative areas (Luhe District of Nanjing, Xinhua County of Taizhou, and Pizhou County of Xuzhou) of Jiangsu Province. A new model for assessing the economic benefit of agro-meteorological services was developed to evaluate the agro-meteorological services economic benefit in these areas. There existed somewhat differences in the key meteorological factors and crucial periods affecting the agricultural economy outputs among the three areas, but air temperature had significant positive effects on the agricultural economy outputs in all areas while precipitation had significant negative effects in Luhe District. With the newly developed assessment model, the contributions of various key meteorological factors to the agro-meteorological services were quantified, and the calculation showed that the economic benefit of agro-meteorological services in Luhe, Xinhua, and Pizhou in 2009 was about 97. 2, 113. 0, and 84. 5 million Yuan, respectively. Source

Chen B.,Nanjing University | Hu W.,Anhui Meteorological Bureau | Pu J.,PLA University of Science and Technology
Journal of Geophysical Research: Atmospheres | Year: 2011

Freezing precipitation (i.e., freezing rain or freezing drizzle) is an extremely hazardous weather that can cause severe socioeconomic loss and compromise human safety. To better document and understand the microphysics of this type of precipitation, drop size spectra were collected with an optical disdrometer during a freezing precipitation event on 27 January 2008 in southern China. The drop size distribution (DSD) characteristics, the correlations between the shape (μ), slope (Λ), and intercept (N0) of the gamma distribution, and the relations between the reflectivity (Z) and rainfall rate (R) have been investigated. It was found that the DSDs of freezing precipitation were characterized by weak stratiform rain with a small mass-weighted diameter (Dm, 0.63 mm) and a large normalized intercept (Nw, 4.25 log10 mm-1 m-3). This indicated that freezing precipitation was not formed by the melting of larger, dry snowflakes but by the melting of smaller, rimed ice particles. Furthermore, the derived μ-Λ, N0-μ, and Z-R relations are distinctly different from the convective rains or tropical stratiform rains reported in the literature. Copyright 2011 by the American Geophysical Union. Source

Liu L.,Nanjing University of Information Science and Technology | Shen R.-P.,Nanjing University of Information Science and Technology | Ding G.-X.,Anhui Meteorological Bureau
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2011

Hyperspectral remote sensing technology can be extensively applied in soil nutrient research due to its three special advantages, high spectral resolution, strong waveband continuity as well as a great deal of spectral information. Based on analyzing the soil organic matter content using hyper-spectral remote sensing technology, soil nutrients status and its dynamic changes can be fully understood, thus providing the scientific basis for guidance of the agricultural production and protection of agricultural ecological environment. The present paper studies the relationship between soil spectrum and soil organic fraction based on spectrum curves (ranging from 350 to 2500 nm) of 34 soil samples, which were collected in Yujiang and Taihe County, Jiangxi Province. First, soil reflection spectrum was mathematically manipulated into first derivative reflectance spectra (FDR) and inverse-log spectra (log(1/R)); second, the relationship between soil spectrum and soil organic fraction was investigated by stepwise multiple linear regression (SMLR) and partial least square regression (PLSR) on the ground of characteristic absorption; third, corresponding estimation model was built and examined. The result conveys that spectral data are compressed by carrying out arithmetic average operation by 10 nm for intervals. The first derivative of the reflectivity is an effective spectrum indicator, in the stepwise multiple linear regression analysis of soil organic matter, for the first derivative transformation, the regression models' precision of establishment and verification increased. The model built by PLSR method based on the characteristic absorption bands precedes that of SMLR. In the PLSR model of soil reflection spectrum and the inverse-log spectra, the test samples' average of relative error is 16% and 17% respectively, the correlation coefficient between retrieval value and measured value is 0.84 and 0.91 respectively, for it's faster to estimate the soil organic fraction. Source

Li J.,CAS Institute of Atmospheric Physics | Yang W.,CAS Institute of Atmospheric Physics | Yang W.,University of Chinese Academy of Sciences | Wang Z.,CAS Institute of Atmospheric Physics | And 5 more authors.
Atmospheric Environment | Year: 2014

The source-receptor relationships (S-R relationships) of PM10 in Northeast Asia were investigated by a three-dimensional regional chemical transport model with emission and meteorological fields in 2010. A model comparison with ground-based measurements, and satellite and lidar remote sensing data showed that the model reproduced well the spatial and temporal distribution of PM10 over Northeast Asia, with correlation coefficients ranging from 0.50 to 0.94 and normalized mean errors (NMEs) of 10-70% at eleven stations. An on-line tracer-tagged module incorporated into the model indicated that self-contribution contributed the greatest percentage of surface PM10 in China, the Korean peninsula and Japan, reaching 48.5%, 41.8% and 39.1%, respectively. The long-range transport from China and offshore along the Asian continent (Bohai bay, China East Sea, China Huang Sea, the Sea of Japan etc.) constituted the second and third major contributing sources in Korea and Japan (13-26%). The naturally produced dust aerosols also contributed significant percentages, averaging 46.5%, 11.7% and 11.0% in China, the Korean peninsula and Japan, respectively. These S-R relationships of PM10 showed high seasonal variability over Northeast Asia. Significant transport was found between city clusters in China, presenting a major challenge to policy makers since most current remediation efforts are confined within one city cluster. © 2014 Elsevier Ltd. Source

Zhang Y.,University of Oklahoma | Hong Y.,University of Oklahoma | Hong Y.,National Weather Center | Wang X.,University of Oklahoma | And 8 more authors.
Journal of Hydrometeorology | Year: 2015

Prediction, and thus preparedness, in advance of flood events is crucial for proactively reducing their impacts. In the summer of 2012, Beijing, China, experienced extreme rainfall and flooding that caused 79 fatalities and economic losses of $1.6 billion. Using rain gauge networks as a benchmark, this study investigated the detectability and predictability of the 2012 Beijing event via the Global Hydrological Prediction System (GHPS), forced by the NASA Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis at near-real time and by the deterministic and ensemble precipitation forecast products from the NOAA Global Forecast System (GFS) at several lead times. The results indicate that the disastrous flooding event was detectable by the satellite-based global precipitation observing systemand predictable by theGHPS forced by the GFS 4 days in advance. However, the GFS demonstrated inconsistencies from run to run, limiting the confidence in predicting the extreme event. The GFS ensemble precipitation forecast products from NOAA for streamflowforecasts provided additional information useful for estimating the probability of the extreme event. Given the global availability of satellite-based precipitation in near-real time and GFS precipitation forecast products at varying lead times, this study demonstrates the opportunities and challenges that exist for an integrated application of GHPS. This system is particularly useful for the vast ungauged regions of the globe. © 2015 American Meteorological Society. Source

Discover hidden collaborations