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Wang R.,Chinese Academy of Meteorological Sciences | Xu X.,Chinese Academy of Meteorological Sciences | Jia S.,Chinese Academy of Meteorological Sciences | Jia S.,South China University of Technology | And 6 more authors.
Atmospheric Chemistry and Physics | Year: 2017

The North China Plain (NCP) has become one of the most polluted regions in China, with the rapidly increasing economic growth in the past decades. High concentrations of ambient O3 and aerosol have been observed at urban as well as rural sites in the NCP. Most of the in situ observations of air pollutants have been conducted near the ground so that current knowledge about the vertical distributions of tropospheric O3 and aerosol over the NCP region is still limited. In this study, vertical profiles of O3 and size-resolved aerosol concentrations below 2.5 km were measured in summer 2014 over a rural site in the NCP, using an unmanned aerial vehicle (UAV) equipped with miniature analyzers. In addition, vertical profiles of aerosol scattering property in the lower troposphere and vertical profiles of O3 below 1 km were also observed at the site using a lidar and tethered balloon, respectively. The depths of the mixed layer and residual layer were determined according to the vertical gradients of lidar particle extinction and aerosol number concentration. Average O3 and size-resolved aerosol number concentration in both the mixed and residual layer were obtained from the data observed in seven UAV flights. The results show that during most of the flights the O3 levels above the top of mixed layer were higher than those below. Such a positive gradient in the vertical distribution of O3 makes the residual layer an important source of O3 in the mixed layer, particularly during the morning when the top of mixed layer is rapidly elevated. In contrast to O3, aerosol number concentration was normally higher in the mixed layer than in the residual layer, particularly in the early morning. Aerosol particles were overwhelmingly distributed in the size range < 1 μm, showing slight differences between the mixed and residual layers. Our measurements confirm that the lower troposphere over the rural area of the NCP is largely impacted by anthropogenic pollutants locally emitted or transported from urban areas. Compared with the historic O3 vertical profiles over Beijing from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC), a strong increase in O3 can be found at all heights below 2.5 km in the decade from 2004 to 2014, with the largest enhancement of about 41.6 ppb. This indicates that the lower troposphere over the northern part of the NCP has experienced rapidly worsening photochemical pollution. This worsening trend in photochemical pollution deserves more attention in the future. © Author(s) 2017.


He H.,Guangxi Meteorological Disaster Mitigation Institute | He Y.,Guangxi Meteorological Disaster Mitigation Institute | Meng C.,Guangxi Meteorological Disaster Mitigation Institute | Long M.,Plant Protection Station of Guangxi | And 2 more authors.
Journal of Natural Disasters | Year: 2014

Based on data of 60 agricultural survey stations during 1988 to 2010, the spatiotemporal characteristics of rice planthoppers occurrence degree in Guangxi Province were studied by methods of EOF, trend coefficients, linear trend and M-K test, etc. Results show that, on the whole, occurrence degree of rice planthoppers is higher for the first half year than for the second half year, and is higher in east than in west of Guangxi. The occurrence degrees in both sequential half years have increased in the past 23 years, but it is more obvious for the second half year. As for the spatial change characteristics change of rice planthoppers occurrence degree in Guangxi, the region is divided into three sub-regions, because rice planthoppers occurrence may relate to climate difference for different sub-regions. In the first half year, a significant upward trend of occurrence degree appeared in northwest Guangxi, and a remarkable abrupt increase occurred in 1994. But the trends were not significant in neither southwest nor east. For the second half year, the rice planthoppers occurrence degree in both northwest and northeast show significant upward trends, and remarkable abrupt changes of increase occurred in 2006 and in 1998, respectively, but the trend of south was not significant.


Liang Y.,Wuhan University of Technology | Tan Z.,Guangxi Meteorological Disaster Mitigation Institute | Luo Y.,Guangxi Polytechnic College
ICCSE 2012 - Proceedings of 2012 7th International Conference on Computer Science and Education | Year: 2012

In order to provide real-time meteorological service and production decision-making guidance for production management department of sugarcane growing area and sugarcane growers, a set of meteorological service system for production management of sugarcane growing area was developed through the integration of the existing expert systems for sugarcane planting and meteorological databases. This paper introduces the system structure design, functional design, database design, and other system design, as well as the application of system. © 2012 IEEE.


Feng Y.,Nanjing Agricultural University | An Z.-C.,CAS Institute of Geology and Geophysics | Sun H.,Guangxi Meteorological Disaster Mitigation Institute | Mao F.,Chinese Academy of Meteorological Sciences
Wuli Xuebao/Acta Physica Sinica | Year: 2010

The fourth generation of comprehensive model of geomagnetic field CM4 is a numerical model in which earth's magnetic field can completely be divided into internal and external parts. In this paper we have calculated and plotted the grid values of internal and external fields of Chinese mainland in every 10 a from 1960 to 2000 by combining CM4 with Taylor polynomial model based on all survey data during 1960-2000, and made more efforts to analyze the whole distribution of crustal anomaly field. Results show that internal field value of northern component X decreased with time. The amplitude was about 750 nT in the period from 1960 to 2000, the trend of external field variation increased in 1960, then gradually decreased about 32 nT until 2000. The internal field value of eastern component Y decreased first, then continuously increased, and its intensities decreased about 40 nT from 1960 to 2000. The trend of external field variation was increased, decreased and increased as time went on, and the external field increased up to about 3.8 nT since 1960. The internal field value of vertical component Z was similar to that of Y, its intensities totally increased about 600 nT. The trend of external field variation decreased and then increased with time, amplitude of which was about 4.6 nT. As for anomalous field, the distributions of components X and Z, total intensity F, and horizontal component H were all negative, the intensities of X and H decreased with longitude while those of Z and F increased. The distributions of Y and declination D were very similar and both of them had positive values in west-central region of China. Their intensities decreased with longitude. The distribution of inclination I was mainly negative, and its intensity increased with longitude. © 2010 Chin. Phys. Soc.


Feng Y.,Nanjing Agricultural University | Pan J.-J.,Nanjing Agricultural University | An Z.-C.,CAS Institute of Geology and Geophysics | Sun H.,Guangxi Meteorological Disaster Mitigation Institute | Mao F.,Chinese Academy of Meteorological Sciences
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2010

Based on survey data of 156 observatories and repeat stations of China, 6 observatories and 36 IGRF points outside the China in 2000, the geomagnetic field models of total intensity(F), declination(D) and inclination(I) are established by Taylor polynomial model and Surface Spline model, meanwhile, the differential for φ (lotitude) and λ (longitude) of models is carried out to calculate the geomagnetic horizontal gradients, respectively. Then the gradients distribution charts of corresponding components in south-north and east-west direction are drawn, from which a comparison between horizontal gradient charts and IGRF10 for 2000 is made, consistency and difference among these three kinds of horizontal gradient are implemented, too. Finally, the spacial distribution of horizontal gradient is analyzed numerically. Results showed that horizontal gradients of F and I varied mainly with latitude, which of F ranged from 7.0 nT/min to 6.0 nT/min while latitude increased, and got the biggest values in the central region (25°∼35°N, 90°∼120° E) of China, I's gradients varied range from 2'/min to 1'/min while latitude increased, D's gradients varied with both latitude and longitude, which ranged from 0.4'/min to -0. 3'/min in north-south direction while longitude increased and -0.1'/min to -0. 4'/min in east-west direction while latitude increased respectively.


Wang Z.,China Tobacco Guangxi Industrial Co. | Chen Y.,Guangxi Meteorological Disaster Mitigation Institute | Mo J.,Guangxi Meteorological Disaster Mitigation Institute | Wang X.,China Tobacco Guangxi Industrial Co.
Tobacco Science and Technology | Year: 2014

In order to monitor crop planting area and predict its production, HJ-1 satellite (No.1 Environment satellite union of A and B) remote sensing data were used to analyze the spectral reflection characteristics of flue-cured tobacco crop and other ground objects. Three vegetation indices, including normalized difference vegetation index (NDVI), difference vegetation index (DVI) and ratio vegetation index (RVI), were calculated and their discrimination of flue-cured tobacco from other ground objects was analyzed and compared. The method for recognition of flue-cured tobacco from remote sensing data was determined, and the planting information of flue-cured tobacco in Jingxi County, Guangxi was extracted with the developed method. The method precision was verified with GPS field sampling data, and the obtained total precision was 92.79% with Kappa coefficient of 0.8374. It suggested that remote sensing technology could be used to obtain tobacco planting information quickly and accurately.


Feng Y.,Nanjing University of Technology | Sun H.,Guangxi Meteorological Disaster Mitigation Institute | Jiang Y.,Nanjing University of Technology | Mao F.,Chinese Academy of Meteorological Sciences
Acta Seismologica Sinica | Year: 2013

In order to investigate the variation of main magnetic field in Chinese mainland during 20th century, the newest global modes, such as IGRF11, CALS3K.4 (3K.4) and GUFM1, were firstly adopted to calculate and analyze the mean values of annual rate of change (MAC) during 1900-1990. Combining the global mode, CM4, and regional model, Taylor polynomial (TY), we analyzed the distribution of annual rate of change (ARC) and MAC with interval of 10 years, based on survey data during 1960-2000, and then made a comparison with that of three global models. Results showed that the MACs are very close based on the models IGRF11, 3K.4 and GUFM1 throughout the 20th century. These three models demonstrated the similar distribution of ARC in China during 1960-2000, which is resulted from the same modeling theory and closed truncation levels. The distributions of ARC based on global and TY models are basically consistent, that is, the X component of ARC decreases with years, and Y, Z, F firstly decrease and then increase. However, there were some tiny differences between global models and TY model, which is caused by the higher density of valid survey data and the usage of regional model. Results also showed that the MAC from TY model is consistent with that from CM4, indicating that the CM4 model is able to ideally reflect the variation of main magnetic field in Chinese mainland.


Feng Y.,Nanjing University of Technology | Sun H.,Guangxi Meteorological Disaster Mitigation Institute | Jiang Y.,Nanjing University of Technology | Mao F.,Chinese Academy of Meteorological Sciences
Acta Seismologica Sinica | Year: 2014

In order to systematically study all non-dipole (ND) magnetic fields (truncation level N=2-10) in China, we studied the spatio-temporal variation of ND magnetic fields with different degree and their energies during the period of 10000 BC-1990 AD based on the newest time-based global model CALS10K.1b. The latest version of IGRF, i.e., IGRF11, was also adopted to compare and verify. Results show that the zero lines of 22, 23 and 24 pole fields mainly moved from middle-northern region to southeastern region of China, from northern to eastern China, and moved from southeastern to northwestern region of China. Except the 26 pole field, all ND fields exhibited “tail raise”. The percentage of ND field accounting for main field oscillated during 10000 BC-1500 AD, and then rapidly increased. The energies of all ND fields changed following almost same trend except the 22 pole field. Around the year 5650 BC, the energy reached high value, and then attenuated with the degree increasing, which indicates that the energy resulting from the Earth core's dynamo attenuates linearly alone with radial distance. The energy of geomagnetic field mainly originates from the Earth's fluid outer core. Comparison of the result based on CALS10K.1b with that from IGRF11 showed that CALS10K.1b's results in this study are more reliable, and their differences mainly result from different data used and modeling methods.


Chen Y.L.,Guangxi Meteorological Disaster Mitigation Institute | Chen Y.L.,Joint Laboratory for GIS Application | Zhong S.Q.,Guangxi Meteorological Disaster Mitigation Institute | Zhong S.Q.,Joint Laboratory for GIS Application | And 4 more authors.
Applied Mechanics and Materials | Year: 2013

TM/ETM data as the base information combined with a digital elevation model are used to analyze the spatial distribution and temporal variation of soil erosion in Guangxi. The results shows that light, medium and strong are the main three levels of soil erosion in Guangxi. The proportions of light and medium soil erosion are higher which are 6.18% and 4.76% respectively. The total area of soil erosion and its degrees exhibit an upward trend since the 1980s. The area of soil erosion in Guangxi increases 4% in the past 20 years. The five levels of soil erosion performance an upward trend mostly. Medium soil erosion is of the biggest change with an increase of 1.29% while acute soil erosion exhibits a smallest change with an increase of 0.49%.


Luo Y.,Guangxi Meteorological Disaster Mitigation Institute | Sun H.,Guangxi Meteorological Disaster Mitigation Institute | He L.,Guangxi Meteorological Disaster Mitigation Institute | Chen Y.,Guangxi Meteorological Disaster Mitigation Institute | Zeng X.,Guangxi Meteorological Information Center
Journal of Natural Disasters | Year: 2014

This paper analyzed the correlation of 635 forest fire samples with FY - 2 ground incident solar radiations and the difference of daily temperatures respectively from 2005 to 2008 in Guangxi. The analysis results confirm the strong correlation between these data. Then, a forest fire risk rating model was constructed considering the ground incoming solar radiations and the difference of daily temperatures as influence weight coefficients of the model. In addition, the index of incoming solar radiations was added into the model as an input parameter with weight values of combustibles taken into account. Experiments with 783 fire disaster samples of Guangxi (2009-2012) were conducted to examine the validation of the model. Results show that the prediction accuracy of the model reaches 82%.

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