High Performance of Imaging Extraction for Infrared Satellite Cloud Image

The isotherm is an important feature of infrared satellite cloud images (ISCI), which can directly reveal substantial information of cloud systems. The isotherm extraction of ISCI can remove the redundant information and therefore helps to compress the information of ISCI. In this paper, an isotherm extraction method is presented. The main aggregate of clouds can be segmented based on mathematical morphology. T algorithm and IP algorithm are then applied to extract the isotherms from the main aggregate of clouds. A concrete example for the extraction of isotherm based on IBM SP2 is described. The result shows that this is a high efficient algorithm. It can be used in feature extractions of infrared images for weather forecasts.

Local Spiral Curves Simulating Based on Hough Transformation and Center Auto-Locating of Developing Typhoon

In the developing phase of typhoon formation, the spiral belt partly emerges in satellite cloud images. This research starts from images and moves on to graphics and then to representation and recognition. Following this route, local spiral cloud belt is segmented from the raw images using image segmentation, the spiral information is extracted using mathematic morphology, and local spiral curves are detected using Hough transformation. The problem of center locating of developing typhoon has finally been solved through a search algorithm of spiral curve. For No. 99082008 cloud image, the result produced by the algorithm in this paper is at 122..3 degree west longitude, 117.5 degree north latitude. The real typhoon center location was at 122.4 degree west longitude, 18 degree north latitude.

REMOTE SENSING OF CLOUD BOTTOM HEIGHT AND CLOUD TEMPERATURE BY INFRARED RADIOMETER

The feasibility of retrieving cloud bottom height (CBH) and cloud bottom temperature (CBT) by infrared radiometer has been studied by simulations with a large number of historical radiosounding data and field obser- vations.The results show that it is feasible to retrieve CBH and CBT by radiometer observation in infrared band. In this paper we also demonstrate simply that through joint observations by a dual-wavelength (1.35 cm and 8.5mm) microwave radiometer and by infrared radiometer (8.5—12.5μm),it is possible to obtain total water vapor,liquid water content in clouds and CBH and CBT.

The TMRT K band observations towards 26 infrared dark clouds:NH_3, CCS, and HC_3N

We present one of the first Shanghai Tian Ma Radio Telescope (TMRT) K Band observations towards a sample of 26 infrared dark clouds (IRDCs).We observed the (1,1),(2,2),(3,3),and (4,4) transitions of NH_(3) together with CCS (2_(1)–>1_(0)) and HC_(3)NJ=2-1,simultaneously.The survey dramatically increases the existing CCS-detected IRDC sample from 8 to 23,enabling a better statistical study of the ratios of carbon-chain molecules (CCM) to N-bearing molecules in IRDCs.With the newly developed hyperfine group ratio (HFGR) method of fitting NH_(3) inversion lines,we found the gas temperature to be between 10 and18 K.The column density ratios of CCS to NH_(3) for most of the IRDCs are less than 10^(-2),distinguishing IRDCs from low-mass star-forming regions.We carried out chemical evolution simulations based on a three-phase chemical model NAUTILUS.Our measurements of the column density ratios between CCM and NH_(3) are consistent with chemical evolutionary ages of 10^(5) yr in the models.Comparisons of the data and chemical models suggest that CCS,HC_(3)N,and NH_(3) are sensitive to the chemical evolutionary stages of the sources.

Galactic center research:manifestations of the central black hole

This review summarizes a few of the frontiers of Galactic center research that are currently the focus of considerable activity and attention. It is aimed at pro- viding a necessarily incomplete sketch of some of the timely work being done on phenomena taking place in, or originating in, the central few parsecs of the Galaxy, with particular attention to topics related to the Galactic black hole （GBH）. We have chosen to expand on the following exciting topics： 1） the characterization and the im- plications for the variability of emission from the GBH, 2） the strong evidence for a powerful X-ray flare in the Galactic center within the past few hundred years, and the likelihood that the GBH is implicated in that event, 3） the prospects for detecting the ＂shadow＂ of the GBH, 4） an overview of the current state of research on the central S-star cluster, and what has been learned from the stellar orbits within that cluster, and 5） the current hypotheses for the origin of the G2 dust cloud that is projected to make a close passage by the GBH in 2013.

A CONVECTIVE RAINFALL ESTIMATE TECHNIQUE DEVELOPED BY NSMC OF CHINA

In order to reveal the relation between strong convective cloud characteristics and rainfall rate, over 20000 hourly raingauge data from 333 weather stations and the corresponding 4000 convective cloud infrared images of GMS-4 during the period of 1992—1994 in Henan,Hubei and Sichuan Provinces were studied.The results show that cloud top temperature,temperature gradient,the growth of cloud,overshooting top and the normalized distance between a cloud covering pixels and the cluster center have certain relations to cloud precipitation.These relations can vary with different geographical regions.Based on the study above,a convective rainfall estimation technique was developed by the scientists in National Satellite Meteorological Center of China.Its average error is 30% for daily precipitation with a correlation coefficient of 0.69.