Liaoning Climate Center

Shenyang, China

Liaoning Climate Center

Shenyang, China
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Wang J.,Beijing Regional Climate Center | Zou L.,China Meteorological Administration Training Center | Zhao C.,Liaoning Climate Center | Lou D.,Qiqihar Meteorological Bureau
Journal of Geographical Sciences | Year: 2011

Based on 1961-2005 observed winter precipitation data in Northeast China, the temporal and spatial variations of snow concentration degree (SCD) and snow concentration period (SCP), together with the circulation characteristics when there is a higher SCD, are computed and analyzed. Results show that SCD in Northeast China presents a yearly rising tendency and SCP decreases obviously. In terms of decadal variation, there is a 12-year periodic variation in PCP, and since the mid-1970s there has been an 8-year short periodic variation. As to spatial variation, SCD in winter of Northeast China has increased gradually from the eastern part to the western, and the minimum value of SCD occurs in the east of Jilin Province, while the high value center is observed in the central part of the province. For the whole Northeast China, the variation tendencies are consistent in the eastern and central parts, where SCD presents a rising tendency and SCP shows a decreasing tendency. SCD in the southwestern and northern parts has a slight rising tendency, with SCD in the southwestern part having the slightest increasing tendency, and SCP in the northern part showing the slightest decreasing tendency. When a high SCD value is observed, the whole region is controlled by the East Asian deep trough at 500 hPa, and the trough becomes deeper in the western part, while a high pressure, which is easily formed and intensified in the eastern part, makes the East Asian deep trough move eastward slowly. Upper-level jet stream and low-level jet stream co-exist, and the former is stronger and takes more of a southwestward position than the latter. The high value zone of water vapor transport over the Pacific is intensified obviously, and the extent also increases. Northeast China is influenced by the water vapor transported to the northwest along the north of the high value center. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.


Wang H.,Nanjing University of Information Science and Technology | Guo F.,Nanjing University of Information Science and Technology | Zhao T.,Nanjing University of Information Science and Technology | Qin M.,Liaoning Climate Center | Zhang L.,Nanjing University of Information Science and Technology
Atmospheric Research | Year: 2016

This study investigates the electrical conditions favorable to the occurrence of positive cloud-to-ground (+. CG) flashes from the forward flank of normal polarity thunderstorm by building a three-dimensional stochastic lightning model and a normal polarity charge structure model. The lightning model well simulated the bilevel branched structure of lightning flash, which has been observed by previous studies. Simulation results indicate that the downshear extension of the charge layer to the forward flank would decrease the electric field of thunderstorm. When only the upper positive charge layer downshear extended to the forward flank, it could not give rise to the occurrence of +. CG flashes. When both the upper positive and midlevel negative charge layers downshear extended to the forward flank, if the charge of the negative charge layer was less than the positive charge layer above it in the forward flank of the thunderstorm, that generated sufficient charge imbalance between these two charge layers, +. CG flashes could originate from the forward flank; otherwise, IC flashes occur. © 2015 Elsevier B.V.


Wang H.,Nanjing University of Information Science and Technology | Guo F.,Nanjing University of Information Science and Technology | Qin M.,Liaoning Climate Center
2014 International Conference on Lightning Protection, ICLP 2014 | Year: 2014

The relationship between the occurrence of +CG lightning and the tilted triple charge structure of thunderstorm is researched by establishing various three-dimensional models of triple charge structure of thunderstorm with a stochastic lightning discharge parameterization scheme. The results show that the horizontal movement of the upper positive charge region can't make the flash type convert from cloud lightning to +CG lightning, but will make the lightning more difficult to occur. When the middle negative charge region is moved in horizontal direction, it will result in more lightning discharges. Meanwhile the potential difference between initial point and ground reduced gradually. Due to this, although the downward propagation of the positive leader will not be blocked by the lower positive charge region, the reduction of the potential difference between the initial point and ground makes the positive leader more difficult to propagate to the ground. In the triple charge structures, when the charge density and scope of upper positive charge region are very large, the positive leader is possible to propagate to ground, driven by local charge and potential imbalance. But the tilt of charge structure will not make the thundercloud inclined to produce +CG. © 2014 IEEE.


Wang J.,Beijing Climate Center | Zhao C.,Liaoning Climate Center | Lou D.,Qiqihar Meteorological Bureau
Acta Geographica Sinica | Year: 2010

Based on 1961-2005 observed winter precipitation data in Northeast China, the temporal and spatial variations of precipitation concentration degree (PCD) and precipitation concentration period (PCP) are computed and analyzed, together with the circulation characteristics when there is a higher PCD. Results show that the PCD in Northeast China presents a yearly rising tendency and the PCP decreases obviously. In terms of decadal variation, there is a 12-year periodic variation in PCP, and since the mid-1970s there has been an 8-year short periodic variation. As to spatial variation, the PCD in winter of Northeast China has increased gradually from the eastern to western part, and the minimum value of PCD occurs in the east of Jilin Province, while the high value center is observed in the central part of the province. For the whole Northeast China, the variation tendencies are consistent in the eastern and central parts. The PCD presents a rising tendency and the PCP shows a decreasing tendency. The PCD in the southwestern and northern parts has a slight rising tendency, with the PCD in the southwestern part having the slightest increasing tendency, and the PCP in the northern part showing the slightest decreasing tendency. When a high PCD value is observed, the areas are controlled by the East Asian deep trough at 500 hPa, and the trough becomes deeper in the western part, while a high pressure, which is easily formed and intensified in the eastern part, makes the East Asia deep trough move eastward slowly. Upper-level jet stream and low-level jet stream co-exist, and the former is stronger and takes more of a southwestward position than the latter. Over the Pacific the high value extent of water vapor transport is intensified obviously, and the extent also increases. Northeast China is influenced by the water vapor transported to the northwest along the north of the high value center.

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