S.4.1 Classification Study on the Relationship between Lightning Activity and Precipitation in Beijing

13/03/2014
Auteurs :
OAI : oai:www.see.asso.fr:9740:9953
DOI :

Résumé

S.4.1 Classification Study on the Relationship between Lightning Activity and Precipitation in Beijing

Métriques

11
3
224.98 Ko
 application/pdf
bitcache://3f4b5a6e463b87b0b1c67953d281610b1b2266da

Licence

Creative Commons Aucune (Tous droits réservés)

Sponsors

Co-organisateurs

ilpa_logo.png
<resource  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xmlns="http://datacite.org/schema/kernel-4"
                xsi:schemaLocation="http://datacite.org/schema/kernel-4 http://schema.datacite.org/meta/kernel-4/metadata.xsd">
        <identifier identifierType="DOI">10.23723/9740/9953</identifier><creators><creator><creatorName>Wen Yao</creatorName></creator><creator><creatorName>TingBo Wang</creatorName></creator><creator><creatorName>Dong Zheng</creatorName></creator></creators><titles>
            <title>S.4.1 Classification Study on the Relationship between Lightning Activity and Precipitation in Beijing</title></titles>
        <publisher>SEE</publisher>
        <publicationYear>2014</publicationYear>
        <resourceType resourceTypeGeneral="Text">Text</resourceType><dates>
	    <date dateType="Created">Wed 26 Feb 2014</date>
	    <date dateType="Updated">Tue 13 Jun 2017</date>
            <date dateType="Submitted">Fri 25 May 2018</date>
	</dates>
        <alternateIdentifiers>
	    <alternateIdentifier alternateIdentifierType="bitstream">3f4b5a6e463b87b0b1c67953d281610b1b2266da</alternateIdentifier>
	</alternateIdentifiers>
        <formats>
	    <format>application/pdf</format>
	</formats>
	<version>32835</version>
        <descriptions>
            <description descriptionType="Abstract"></description>
        </descriptions>
    </resource>
.

Classification Study on the Relationship between Lightning Activity and Precipitation in Beijing Wen Yao State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences Beijing, China TingBo Wang Chinese Meteorological Administration Training Centre Beijing, China Dong Zheng State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences Beijing, China Abstract—This paper chose a total of 28 thunderstorms occurring in Beijing area from 2006 to 2008. It aimed to investigate the relationship between the total lightning (obtained by SAFIR3000) and convective precipitation (inverted from radar). These cases were classified according to the parameters of the local atmospheric stratification and the reflectivity of radar. Rainstorm and hailstorm were further chosen for the comparison of their lightning activities and the relationship between lightning and precipitation. The analysis result showed that the general relationship between the lightning and convective precipitation, on the whole, the average convective rain-yield per flash (RPF) is 1.92×107 kg/fl, while the linear correlation coefficient between the total flash rates and RPF is 0.584. These 28 thunderstorms are classified according to the Convective Available Potential Energy (CAPE) and Lifting index (LI) of the atmospheric stratification where they are generated. It is explored that strong instability of atmospheric stratification tends to be associated with smaller RPFTL (TL: total lightning) and more pronounced correlation between total lightning and precipitation. Of which, the classification of CAPE ≥ 1600 J/kg has the correlation coefficient of 0.837, while the classification of LI ≥ 4 K has the correlation coefficient of 0.853. At the meantime, these thunderstorms are classified according to the following parameters of the radar reflectivity, maximum height of 20-dBZ reflectivity (H20dBZ) and volume ratio of the reflectivity larger than 30 dBZ above 0 ℃ to the reflectivity larger than 40 dBZ above 0 ℃ (VR40/30), in term of their radar volume scans. The most pronounced relationships between lightning and precipitation occur in the classification of H20dBZ < 11.5 km, and VR40/30 < 0.39, while the correlation coefficients are 0.804 and 0.750, respectively. Keywords—Precipitation; Lightning; Correlation; Contrastive Analysis INTRODUCTION The relationship of lightning and precipitation is a scientific problem concerned in recent years, The relationship is complex, which is dependent on the dynamic and microphysical processes to some extent. On the one hand, in the thunderstorms with strong convection, the intensity of lightning activity and convective motion is close with the ice phase process in the cloud; on the other hand, convection is also the key reason for the heavy rainfall produced by strong thunderstorms. So there is an intrinsic link between lightning and precipitation, meanwhile, lightning and rainfall are important objects of weather detecting, warning and nowcasting. With the development of lightning location technology, the role of lightning data in convective weather monitoring is prominent increasingly. Precipitation estimation based on lightning data, can provide a complement to the tools of rainfall warning, and it has also an important reference for assimilation of numerical weather model. was 104 - 105 km2 ,they found that RPFcG was about 108 kg/fl in the middle continent of USA., and 6×107 kg/fl in the southwestern; 4×108 kg/fl in the tropical mainland; the value of RPFcG was 1010 kg/fl in the tropical western Pacific. Zheng Dong et al. analyzed the relationship of lightning and rainfall using the total lightning data of Beijing, the value of RPFTL(total lightning) was in the range of 0.86~6.57×107 kg/fl, the average value was 2.65×107 kg/fl. The relationship between lightning and rainfall also changed varies with climate, Petersen and Rutledge found that the correlation coefficient of ground lightning and convective rainfall was 0.71, 0.45, 0.87, and 0.90 in the southeast, northeast, central and southwest of USA respectively. Research showed that RPF had a great change, even several magnitude orders, in different regions, but Petersen ,Rutled and Ziper pointed that the relationship of lightning and rainfall id stable relatively in a certain area. . In recent years, a large number of observations have revealed that the change of lightning intensity and frequency was ahead of the peak of rainfall. Williams et al. (1999) found that the peak of total lightning frequency was 5-20 minutes ahead of the strong weather phenomena on the ground in Florida. Piepgrass et al. also found that rainfall peak occurred in 10 minutes before or after the peak time of total lightning. Some studies have also noted that the spatial relationship between lightning and precipitation. Reap and MacGorman, Orville and Silver found that the region produced strong lightning also appeared the strongest regional precipitation. In addition, It also found that the distribution of positive and negative ground flashes in some thunderstorms was often different, which may corresponded to the region of different precipitation. Rain-yield per flash (RPF) is an important parameter reflects the relationship between lightning and rainfall. The RPF has differences in different regions. Pineda et al. analyzes 9 thunderstorm cases occurred in the northwestern Mediterranean region, the average value of RPFcG was 38.9 ×103 kg/fl, range from 10.8~87.2×103 kg/fl. Petersen and Rutledge calculated the relationship between It has a certain degree of consistency in the development of strong convective precipitation and the trend change of the lightning activity. But the relation is complex with the difference of thunderstorms intensity, area and climatic zone, and the atmosphere environment. So it is necessary to study the relationships of lightning and rainfall according to the change of lightning activity and rainfall intensity, and obtain the quantitative analysis result, provide the parametric relationship of lightning and precipitation. DATA AND METHOD A. Lightning data SAFIR (Systeme d’Alerte Fondre par Interferometrie Radioelectrique) is a multiple site VHF (very high frequency) lightning detection system. The network of the Beijing-Tianjin-Hebei region is composed of three VHF interferometers of the SAFIR type (Yongqing, Fengrun, Huairou) and a center station (Beijing). The expected flash detection efficiency is 90%, with a maximum location accuracy of 2 km within 200 km. Several VHF sources were determined by SAFIR. To automatically determine whether each covered point belongs to the same lightning Precipitation and lightning in the number of places, the research period of time was 1 month, and the space range discharge, the following criteria are used in identifying a given ‘‘flash’’. 1) The continuous time for one IC lightning discharge is the maximum of 100ms; the continuous time for one CG lightning discharge is the maximum of 500ms. 2) The horizontal motion distance of a lightning discharge is the distance between adjacent covered points and does not exceed 7 km. 3) To provide an accurate study, several positive flashes reported by the SAFIR network were eliminated from the original dataset. The criterion to validate a positive CG flash was based on a threshold minimum for the peak current value fixed to 10 kA. B.Radar Data Radar data are extensively used in this study for cell identification and comparison with lightning data. The data from S-band Doppler weather radars located in Daxing District, Beijing City, (Location: E116.47°, N39.81°) was used to analyze these cases. For convenience of analysis, the reflectivity of the original polar scan data were converted to Cartesian coordinates, with 21 layers in the vertical direction by bilinear interpolation methods, in which 0.5-5.5 km were divided into 11 layers with a 0.5 km interval; 6-10 km were divided into 5 layers with 1 km interval; 11-20 km were divided into 5 layers with 2 km interval, and its horizontal resolut-ion was 0.01 x 0.01 degrees. The scope were primarily identified from radar reflectivity plots and the lightning activity images, the region of 20 dBZ radar reflectivity should be selected, and no continuous lightning activity near the cell edge. C Convective precipitation calcution method This research focus on the precipitation in thunderstorms convection area. It was using the methods of Steiner to identify convective or stratus area, then select reflectivity factor of 3 km height to calculate the precipitation rate. The classic convective precipitation formula was adopt, that was Z=300×R1.4 , in which, Z(mm6 /m3 ) is the reflectivity factor of 3 km height, R (mm/h) denote the rainfall rate. The RPF was calculated through convective precipitation divided by lightning frequency of the corresponding time period (6min in general). RESULT A. Relationship between lightning and rainfall in Beijing The selected thunderstorm cases in Beijing region were studied systematically, based on the lightning monitoring data from SAFIR. Through the study of 28 cases, the analysis of the lightning activity and precipitation was presented. RPF in Beijing was range from 1.84×105 kg/fl to 7.91×107 kg/fl, the average value was 1.92×107 kg/fl. The RPF of cumulative distribution 5 % and 95% respectively was 2.69 × 106 kg / fl and 6.05 × 107 kg / fl. From Fig.1,it showed that log(RPF) distributed in 6.5- 7.that is the RPF ranged from 3.16×106 kg/fl to3.16× 107 kg/fl, Fig.2 was the scatter plot of lightning frequency and convective precipitation, from the result of linear fit, the linear correlation coefficient is 0.584,the linear regression equation is R = (2.813×108 ) + (4.570×106 )F, where R denoted convective precipitation(kg/6 min),F is lightning frequency of Total lightning from SAFIR. Fig. 1 Distribution of log(RPF) Fig.2 Scatter plot of total lightning frequency and convective precipitation and its linear fitting B. Relationship between lightning and rainfall in different classification criteria of stratification parameters Instability parameters of 28 cases were analyzed in the text, such as CAPE and Lifted Index. The study classified the CAPE into three categories: CAPE < 1000 J/kg,1000 J/kg ≤ CAPE < 1600 J/kg and CAPE ≥ 1600 J/kg. The statistics of RPF based on CAPE was obtained in table.1. The RPF corresponding to a large CAPE was relative small. We also had a statistic result base on the LI, similarly to the CAPE, Large LI (LI≥4K) also correspond to a smaller RPF. Through the analysis of stratification parameters, it got that with the increase of atmospheric stratification instability, RPF has a decreasing trend. AM* : Arithmetic Mean; GM*: Geometric Mean; Mid*:Median Value. C. Relationship between lightning and rainfall in different radar parameters The height of 20dBZ of radar reflectivity as cloud top can reflect the strength of convective activity to a certain extent. Through the linear fit results, we got that it is obvious between lightning and convective precipitation in H20dBz<11.5km. The smaller H20dBz may be corresponding to the development or extinction of thunderstorm, when the lightning and precipitation had the characteristic of increase and reduction together, the relationship is more apparent. The linear correlation coefficient was 0.853. But when the lightning and the rainfall were all active, the thunderstorm was in the vigorous stage, the relationship may be more complicated and had relative weak correlation. The linear correlation coefficient was 0.663. Volume ratios of the reflectivity larger than 30 dBZ above 0 ℃ to the reflectivity larger than 40 dBZ above 0 ℃(VR40/30)can reflect the ratio of core discharge area in the whole electrification. The value of VR40/30 is larger when the thunderstorm in the development stage. We studied the RPF distribution in the criteria of VR40/30 < 0.39,0.39 ≤ VR40/30 < 0.48,and VR40/30 ≥ 0.48. From the results, it was known that VR40/30 ≥ 0.48 corresponds to the large RPF and 0.39 ≤ VR40/30 <0.48 corresponds to the small RPF. Consider the extent level of thunderstorm, small ice-phase particles were not transported to distant area that is it was in the development of thunderstorm, at this time the RPF was large, and this conclusion is also consistent with the conclusion of result A and B. The Stronger convection thunderstorms is (or stronger convective thunderstorm stages), the relatively smaller RPF is. CONCLUSION 28 thunderstorm cases in Beijing were selected to study the relationship between the total lightning and convective precipitation. The analysis was based on atmospheric stratification and the reflectivity characters of radar. It is found that: Table 1. The statistics of RPF based on CAPE CAPE (J/kg) <1000 1000~1600 ≥1600 N (%) 156(45%) 123(35%) 68(20%) Min (×105 kg/fl) 1.84 6.80 5.00 Max (×107 kg/fl) 6.81 11.50 5.37 AM *(×107 kg/fl) 1.98 2.02 1.50 GM *(×107 kg/fl) 1.30 1.22 1.13 Mid* (×107 kg/fl) 1.55 1.25 1.08 1) The average convective rain-yield per flash (RPF) is 1.92×107 kg/fl, while the linear correlation coefficient between the total flash rates and RPF is 0.584. 2) According to analysis of the Convective Available Potential Energy (CAPE) and Lifting index (LI) of the atmospheric stratification, it found that with the enhancement of instability, RPF has a decreasing trend. 3) From the characteristics of radar, it showed that The Stronger convection thunderstorms is (or stronger convective thunderstorm stages), the relatively smaller RPF is. The most pronounced relationships between lightning and precipitation occur in the classification of H20dBZ < 11.5 km and VR40/30 < 0.39, while the correlation coefficients are 0.804, 0.609 and 0.750, respectively. REFERENCES [1] Soriano L R, and Pablo F D. Analysis of convective precipitation in the western Mediterranean Sea through the use of cloud-to-ground lightning [J]. Atmos. Res., 2003. 66: 189–202. [2] Alexander G D, J A Weinman, V M Karyampudi, et al. The effect of assimilating rain rates derived from satellites and lightning on forecasts of the 1993 superstorm [J]. Mon. Wea. Rev., 1999. 127: 1433-1457. [3] Williams, E. R., . The tripole structure of thunderstorms. J. Geophys. Res.,1989. 94: 13151– 13167. [4] Rutledge, S. A. and D. R. MacGorman. Cloud-to- ground lightning activity in the 10-11 June 1985 Mesoscale Convective System observed during the Oklahoma-Kansas PRE-STORM Project. Mon. Wea. Rev., 1988. 116: 1393-1408. [5] Williams, E. R., B. Boldi, A. Matlin, et al. The behavior of total lightning activity in severe Florida thunderstorms. Atmos. Res., 1999. 51: 245-265. [6] Piepgrass, M. V., E. P. Krider, and C. B. Moore. Lightning and surface rainfall during Florida thunderstorms. J. Geophys. Res., 1982. 87(C13): 11193- 11201. [7] Reap, R. M., and D. M. MacGorman. Cloud-to- ground lightning: Climatological characteristics and relationships to model fields, radar observations and severe local storms, Mon. Wea. Rev., 1989. 117: 518-535. [8] Orville, R. E., and A. C. Silver. Lightning ground flash density in the contiguous United States: 1992-1995. Mon. Wea. Rev., 1997. 125: 631-638. [9] Stolzenburg, M. Observations of high ground flash densities of positive lightning in summertime hunderstorms. Mon. Wea. Rev., 1994. 122: 1740-1750. [10] Williams E R, S G Geotis, N Renno, et al. A radar and electrical study of tropical “hot towers” [J]. J. Atmos. Sci., 1992. 49: 1386-1395. [11] Pineda N, T Rigo, J Bech, et al. Lightning and recipitation relationship in summer thunderstorms: Case studies in the North Western Mediterranean region [J]. Atmos. Res., 2007. 85: 159-170. [12] Petersen W A and S A Rutledge. On the relationship between cloud-to-ground lightning and convective rainfall [J]. Journal of Geophysical Research, Volume 103, Issue D12., 1998. p: 14025-14040. [13] Ziper E J. Deep cumulonimbus cloud systems in the tropics with and without lightning [J]. Mon. Weather Rev., 1994. 122: 1837-1851. [14] Young, K. C. Microphysical Processes in Clouds, 1993. Oxford University Press. [15] Musil, D. J., and P. L. Smith. Interior characteristics at mid-levels of thunderstorms in the southeastern United States. Atmos. Res.,1989. 24: 149-167. [16] Soriano L R, F de Pablo, E G Diez. Relationship between convective pre cipitation and cloud-to-ground lightning in the Iberian Peninsula [J]. Mon. Wea.Rev., 2001. 129: 2998-3003. [17] Pessi A, S Businger, K L Cummins, et al. On the relationship between lightning and convective rainfall over the central pacific ocean [J]. 18th International Lightning Detection Conference, 7-9 June 2004, Helsinki, Finland, 2004.REF. NO. 21.