Overview of Advances in Synoptic Meteorology:Four Stages of Development in Conceptual Models of Frontal Cyclones

The advance of fluid dynamics may be divided into four stages： ancient, classical, neoteric, and contem- porary. A similar four-stage framework can be used to describe the advance of synoptic meteorology, such as the conceptual models of extratropical cyclones and their attendant fronts. The first conceptual model of extratropical cyclones was proposed by Admiral FitzRoy in 1863. Based purely on Admiral FitzRoy＇s personal experience （although it does contain some scientific essentials）, this model represents the “ancient” stage of synoptic meteorology. The Norwegian cyclone model was developed based on Newtonian mechanics about 100 yr ago, and represents the classical stage of synoptic meteorology. This model was based on the idea that weather changes are primarily caused by baroclinicity, but contain some serious flaws. In particu- lar, the Norwegian model regards fronts as zeroth-order discontinuities in density, which is inconsistent with the continuity principle of fluid dynamics. The Chicago three-dimensional conceptual model of fronts and cyclones, which was developed approximately 50 yr ago by using quasi-geostrophic theory, can be thought of as representing the neoteric stage of synoptic meteorology. The Chicago model was replaced in the late 20th century by a model of extratropical cyclones characterized by back-bent and wrap-up warm fronts. This model has been developed with massive numerical calculations, and represents the contemporary stage of synoptic meteorology. In the era of large data, contemporary synoptic meteorology should be careful to maintain and make full use of the profound physical understanding generated during the neoteric stage of synoptic meteorology.

Synoptic Verification of Precipitation Forecast of Three NWP Models from May to August of 2008 in Liaoning Province

In order to evaluate the precipitation forecast performance of mesoscale numerical model in Northeast China,mesoscale model in Liaoning Province and T213 model,and improve the ability to use their forecast products for forecasters,the synoptic verifications of their 12 h accumulated precipitation forecasts of 3 numerical modes from May to August in 2008 were made on the basis of different systems impacting weather in Liaoning Province.The time limitations were 24,36,48 and 60 h.The verified contents included 6 aspects such as intensity and position of precipitation center,intensity,location,scope and moving velocity of precipitation main body.The results showed that the three models had good forecasting capability for precipitation in Liaoning Province,but the cupacity of each model was obviously different.

Lizi Synoptic Model for Rainstorm Forecast and its Applicable Sample

[Objective] The paper was to analyze lizi synoptic meteorology of 13 rain- storm processes during the flood season of Hunan Province in 2010. [Method] Using the principle of lizi synoptic meteorology, 13 regional rainstorm weather processes occurred in Hunan Province in 2010 were analyzed. [Result] Thirteen rainstorms are all closely related to self-organization convergent airflow, rainstorm is the inevitable result after the outbreak of self-organization convergent airflow. The inoculation area of self-organization convergent airflow is accorded with the occurrence area of rain- storm in the next 12-36 h; once the inoculation area of self-organization convergent airflow disappears, there will be no regional rainstorm in the next 12-36 h; the inoc- ulation area of self-organization convergent airflow is produced in the convergence domain of large scale of southern and northern lizi pair. [Conclusion] The existence of southern and northern lizi pair can be used as the short-term forecast model of regional rainstorm during flood season.

Local Meteorological and Synoptic Characteristics of Fogs Formed over Incheon International Airport in the West Coast of Korea

Fogs observed over Incheon international airport （IIA） in the west coast of Korea from January 2002 to August 2006 are classified into categories of coastal fog, cold sea fog, and warm sea fog based on the areal extent of the fogs and the difference between the air temperature （T ） and the SST, i.e., cold sea fog if TSST = T -SST 〉 0~0C and warm sea fog if TSST 〈 0~0C. The numbers of coastal, cold, and warm sea fog cases are 64, 26, and 9. Coastal fogs form most frequently in winter, while cold sea fogs occur mostly in summer and warm sea fogs are observed from January to May but not in November and December. On average the air gets colder by 1.6~0C during the three hours leading up to the coastal fog formation, and an additional cooling of 1.1~0C occurs during the fog. The change in the dew point temperature （T_d） is minimal except during the fog （0.6~0C）. Decreases in T for the cold and warm sea fogs are relatively smaller. The average Td is higher than SST during the cold sea fog periods but this T_d is more than 4~0C higher than that for the corresponding non-fog days, suggesting that cold sea fogs be formed by the cooling of already humid air （i.e., T_d〉SST）. Increases of T_d are significant during the warm sea fog periods （1.4~0C）, implying that effcient moisture supply is essential to warm sea fog formation. Four major synoptic patterns are identified in association with the observed fogs. The most frequent is a north Pacific high that accounts for 38% of cases. Surface or upper inversions are present in 77%, 69%, and 81% of the fog periods for coastal, cold, and warm sea fogs, respectively.

STATISTICAL AND COMPOSITE ANALYSIS OF RELATIONSHIP BETWEEN THE NUMBER OF CONVECTIVE CORES AND THE CHARACTERISTICS OF TBB WITHIN THE TROPICAL CYCLONE CIRCULATION AND ITS INTENSITY

Based on the data(including radius of maximum winds) from the JTWC(Joint Typhoon Warning Center),the tropical cyclones(TCs) radii of the outermost closed isobar, TCs best tracks from Shanghai Typhoon Institute and the Black Body Temperature(TBB) of the Japanese geostationary meteorological satellite M1 TR IR1, and combining13 tropical cyclones which landed in China again after visiting the island of Taiwan during the period from 2001 to2010, we analyzed the relationship between the number of convective cores within TC circulation and the intensity of TC with the method of convective-stratiform technique(CST) and statistical and composite analysis. The results are shown as follows:(1) The number of convective cores in the entire TC circulation is well corresponding with the outer spiral rainbands and the density of convective cores in the inner core area increases(decreases) generally with increasing(decreasing) TC intensity. At the same time, the number of convective cores within the outer spiral rainbands is more than that within the inner core and does not change much with the TC intensity. However, the density of convective cores within the outer spiral rainbands is lower than that within the inner core.(2) The relationship described above is sensitive to landing location to some extent but not sensitive to the structure of TC.(3) The average value of TBB in the inner core area increases(decreases) generally with increasing(decreasing) of TC intensity, which is also sensitive to landing situation to some extent. At the same time, the average value of TBB within the outer spiral rainbands is close to that within the entire TC circulation, and both of them are more than that within the inner core. However, they do not reflect TC intensity change significantly.(4) The results of statistical composite based on convective cores and TBB are complementary with each other, so a combination of both can reflect the relationship between TC rainbands and TC intensity much better.

Comparison study of environmental influences on the intensification of different deep Changjiang-Huaihe cyclones over the East China and Yellow Seas

Abstract： Statistical classification of the intensification of different deepChangiang-Huaihe Cyclones （CHCs） over the East China and Yellow Seas （ECYSs）during 2008 to 2012 is studied using the FNL reanalysis data. Based on the penetrationdepth and the season of occurrence, the CHCs are divided into four categoriesincluding warm-season-deep （WSD）, warm-season-shallow （WSS）, winter-shallow（WTS） and early-spring-bottom （ESB）. Statistics show the CHCs take either aneastward or a northeastward path after entering ECYSs. After moving to the seas, theintensification of CHCs is more significant in cold season than that in warm season.They all have the reduction of the friction of the underlying surface and the increase ofthe near surface winds. The area of strong winds extends and migrates from the east tothe southeast of the CHCs. A significant increase of precipitation during the warmseasons is consistent with the penetration depth of the cyclones. While a slight increaseof precipitation in cold season cyclones and scattered precipitation is observed behindthe ESB cyclones in the early stage of spring. Synthetic diagnosis analysis of the CHCsover ECYSs shows that the latent heat release plays an important role in theamplification of cyclones during the warm season. The ESB cyclones are sensitive tothe dynamic and thermal effects from the underlying surface. The vertical stretching of the positive vorticity volume is much more significant in ESB cyclones than that in othercyclones. The height of maximum upper level divergence is proportional to thepenetration depth of the cyclone for all the categories. Diabatic heating from the underlying surface is more prominent in cold season cyclones. Downward transport ofthe kinetic energy from upper level jet and the reduced friction both have positivecontributions to intensification of the CHCs. Moist Potential Vorticity （MPV） has morecontribution to the intensification of warm season cyclones, especially WSD cyclones.The combined effects from inertial stability and shear stability are beneficial to theamplification of the cyclones in cold season. The position and strength of thetemperature and moisture front from MPV2 term at 1000 hPa coincides with the areaand intensity of precipitation, which shows that the MPV2 is an effective reference forCHCs rainfall forecast.