XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, 2002

Transcription

1 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, Preliminary Results of 3D Rainfall Structure Characteristics of the MCS Observed in the Amazon during the LBA field campaign Carlos A. Morales Universidade de São Paulo, Departmento de Ciências Atmosféricas Luiz A.T. Machado and Henri Laurent Centro Técnico Aeroespacial/Instituto de Aeronáutica/Divisão de Ciências Atmosféricas Abstract: This paper presents for first time a preliminary analyses of the vertical structure of precipitation in Mesoscale Convective Systems (MCS) observed in the Amazon basin during the LBA field campaign by combining measurements of the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and the infrared brightness temperature of the GOES- satellite. This study depicts the life cycle vertical structure as a function of radius and lifetime duration, as wells by MCSs generated by split and merge configuration. A total of 33 TRMM-PR matched MCSs have been analyzed during the period of January and February 199. The MCSs present an intensification of liquid water content in the lower km and the ice content above as a function of size and lifetime duration increase. The growth ratio shows that less intense systems have their highest development during it mature stage, while the most explosive systems are associated to its initial development. Split generation convective systems are more intense than spontaneous generation to all sizes and lifetime duration. In another hand, the merge generation convective system present less intensity than the spontaneous generation convective systems. 1. Introduction Tropical convection is mostly organized in cloud clusters also called mesoscale convective systems (MCS) [e. g., Cotton and Anthes, 199 or Houze, 1993]. The Wet season Amazon Mesoscale Campaign (WET- AMC) held in January-February 1999 as part of the Large-scale Biosphere Atmosphere experiment (LBA) has provided an extensive set of observations of the physical climate in southwestern Amazon [Silva Dias et al., 1]. Besides, several other instruments to measure precipitation as part of the ground validation of the TRMM satellite [Tropical Rainfall Measuring Mission, Simpson et al., 199] were also set up with the WETAMC. This field campaign took place in the Rondônia state in Brazil during January and February The combined WETAMC/LBA and TRMM/LBA campaigns represent a major effort to understand the tropical convection in Amazon. Throughout the globe, satellite measurements are extensively used to study these convective systems, since weather radars are not available over a large scale. Infrared and visible sensors onboard of geostationary satellites are commonly used because of their high temporal resolution that makes possible to track the cloud systems along their life cycle [e. g., Maddox, 19, Mapes and Houze, 1993, Chen et al., 199, Hodges and Thorncroft, 1997, Machado et al., 199, Mathon and Laurent,, among others]. Few studies were devoted to South America [Velasco and Fritsch, 197, Machado et al., 199]. This paper describes the vertical structures of the convective systems during the different phases of the life cycle.. Data and Methodology This study uses the precipitation radar (PR) of the Tropical Rainfall Measuring Mission (TRMM) (Simpson et al. 19 and Kummerow et al. 199) and the Geostationary Operational Environmental 37

2 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, Satellite (GOES-) infrared images (channel, wavelength ~ 11 µm) during the period of January 11 th through February 7 th of The region of analyses consists of 9W-3W and S-5N. The TRMM satellite is a non-sun-synchronous satellite orbiting at ~35 km above the surface, thus covering the latitude belts of 35N and 35S. The TRMM-PR operates in the frequency of 13. GHz. The PR antenna beam scans in the cross-track direction over ± 17 o at. seconds. The beam width is.71 o that represents 9 scan angles. The horizontal resolution of this footprint is.3 km at nadir and about 5 km at the scan edge (±17 o ). Therefore the PR swath for this configuration is ~15 km. The vertical beam width is 5 m. The available PR data consists of the first bins or km above the Earth s geode. The minimum detectable radar reflectivity factor (Z) is ~15 dbz. Since the PR frequency suffers from significant rain attenuation, the measured reflectivity factor is corrected by attenuation using a hybrid method that consists of the Hitschfeld-Bordan iterative scheme and the surface reference technique (Iguchi and Meneghini, ). The measured radar reflectivity factor is converted to rainfall rates by assuming different drop size distributions observed in the Tropics (Iguchi et al. ) that are characteristics of convective and stratiform precipitation. The identification of convective and stratiform rainfall pixels is subject of horizontal (Steiner et al. 1995) and vertical characteristics (Awaka et al and 199). The PR data was acquired from the Distributed Active Archive Center (DAAC) of NASA-GSFC, and consists of the rainfall sub-products named: A5 and A3. These TRMM-PR sub-products have the vertical profiles of attenuation correction radar reflectivity factor and converted rainfall rate, rain type classification (convective, stratiform and others), height of the freezing level and bright band, storm height, latitude, longitude and scan time for each pixel sampled. The GOES- images were ingested and pre-processed by NASA-GSFC GOES project science. Raw data were converted to brightness temperature and stored in -bit TIFF images. Navigation files were created periodically during this period. The horizontal resolution of these images is x km at nadir. During the WETAMC/LBA experiment the images were ingested every 3 minutes, according to NOAA-GOES scanning strategy. Convective systems are commonly detected in the infrared channel images of geostationary satellites. The basic assumption is that low brightness temperatures are associated with deep convection. This assumption is valid for tracking tropical convective systems over their whole life cycle, since in these regions thick Cirrus are likely to be generated by deep convection. A cold brightness temperature threshold selects Cirrus anvils that can last longer than the deep convection. Therefore the convective system tracking takes into account the dissipation phase of the system when convection is no more active. In this study no attempt is made to distinguish between the convective and the stratiform regions of the convective cloud systems using the GOES-IR (this information is obtained with coincident TRMM-PR measurements). However the very deep convective areas that can be embedded in the convective shields are generally associated to high top cloud and therefore a colder temperature threshold. In this preliminary study we use the threshold 35 K to define a contiguous cloud cluster, according to the methodology developed by Laurent et al. [] and Machado et al. [1]. The cloud cluster tracking method is detailed in Mathon and Laurent [], and in this study we use the same results obtained by Laurent et al. []. In that study, a MCS is defined as cloud area of a minimum pixels, i.e. ~ 3,5 km. The cloud tracking algorithm produces time series of size, location, ellipsoidal shape, temperature histogram, and split and merge generation for each individual MCS observed during the period mentioned above. For more details of the cloud tracking algorithm and definitions used, the reader is encouraged to read Laurent et al. []. In addition to these parameters, we also compute the life cycle stage of the clouds according to its area development in time. In our study, we define the life cycle stages as: initial, maturity and decay processes. The next step for matching the PR measurements with the cloud cluster tracking consists in using additional information of the infrared channel (. µm) of the Visible Infrared Radiometer Sensor (VIRS) on board TRMM. Since VIRS and PR observe the same area, we delineate the clouds observed by VIRS 3

3 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, with temperatures lower than 35 K. For each contiguous cloud delineated, we extract the coincident PR measurements. Therefore, we store individual cloud files that have all the raining pixels characteristics. For each matched PR-VIRS cloud we compute the mean radar reflectivity factor profile for convective and stratiform rain type, the surface rainfall distribution, rain area, ellipsoidal shape and the latitude and longitude of the center of mass. Subsequently, we searched for coincident PR-VIRS raining clouds and the individual MCSs time series obtained in the cloud tracking. During the period of this study, we found 33 coincident matches. Upon the match between the GOES-MCS (cloud tracking) and the raining PR-VIRS cloud, we store the files according to the size, lifetime duration and life cycle stage. In the following section we inspect the different characteristics of the vertical structure of precipitation according the size and lifetime duration of the observed MCS. Finally, we also explore in terms of split and merge generation and growth ratio. 3. MCS 3D Rainfall Characteristics 3.1 Radius The life cycle characterization as function of radius is divided in three radius categories: -5 km; 5- km, > km. In applying this size separation, we expect to differentiate the systems that are associated with local effects to large-scale circulation. Figures 1a through 1f present the mean vertical profile and cumulative surface rainfall distribution for the different size classes as well convective and stratiform rain type. The main characteristic of the vertical structure of precipitation observed from Figures 1a, 1c and 1e is the increase of liquid water content (LWC) in the lower km above surface and the presence of ice particle above km as the MCS size increases. Additionally, to the storm intensification, the storms become taller with the increase in size. The small MCSs (< 5 km), Figures 1a and 1b, do not present intense convection trough its entire life cycle. The rainfall distribution shows that most of the precipitation arises from rainfall rates lower than 5 mmh -1. These systems are most intense in their initial stage of development, where it shows most of the LWC and higher surface rainfall rate and no intensification of the bright band at km. As these systems grow, the large particles, such as graupel and snow begin to melt and there is intensification of the bright band. Since these particles are smaller as they fell a secondary evaporation process is more evident at the surface. In the later development of these storms (mature), the collapse of the system is evident due to the increase in reflectivities at the bright band and at the surface in respect to the mature stage. The medium MCSs (5- km), Figures 1c and 1d, present some features on its development. The mean profiles are very similar through the entire rain cycle. The mean distinction is in the mature stage, where higher concentration of ice particles is evident between and 1 km, and its subsequent bright band intensification. This effect is also reflected in the surface rainfall, since large particles are proportional to higher rainfall rates at surface. The large MCSs (> km), Figures 1e and 1d, which are most observed in the Amazon (Laurent et al. ), show two distinct features in the vertical structure. First, at the initial stage, there is intensification at higher altitudes above km due to the presence of higher concentration of ice particles. This process might explain the fuel for large systems that tend to last for several hours or days. Second, in their decay process, there is an increase of reflectivities near the surface, which can be associated to the large particles that have been created during the mature stage. At the surface rainfall distribution, most of the intense precipitation is observed during the initial development, which might be linked to the intensification of the initial stages that can be related to higher updrafts and downdrafts. 39

4 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, 3. Lifetime The lifetime period of such MCSs can reveal the different time scales involved in the convection that, consequently linked to local and large-scale process. For small lifetime scales it is expected that such system are associated to localized convection while longer duration are the response of large organized systems. The corresponding lifetime scales to the size dimension presented in the above section, according to Laurent et al. (), would be: < hours for radius < 5 km; to hours for radius between 5 and km and above hours for radius above km. Unfortunately, due to the limited amount of matched samples in this interval, any physical interpretation would be bias. Therefore, we present in Figures a through f the mean vertical profile and surface rainfall distribution for different lifetime duration intervals: < h, - h and above h. In applying these time interval, the population of convective systems (CS) having life time smaller than hours correspond, in average, to CS with radius smaller than km. Thus the behavior of these CS with lifetime smaller hours is very similar to that of smaller and medium size discussed in the previous section. The CS with lifetime larger than hours and smaller than 1 day correspond to nearly all population of large CS, and presents the same characteristics observed in CS larger than km. The intensification of the MCS with lifetime duration is not so strong as with size, nevertheless there is a slight increase, since we are not presenting the corresponding lifetime and radius relationship. For MCS systems with lifetime lower than hours, Figures a and b, the maximum development is observed in its mature stage, which is characteristic of localized convection. The stratiform rain type also shows no intensification of the bright band. Consequently, the presence of considerable vertical movement inhibits the melting of ice particles. For MCS systems with lifetime duration between to hours, Figures c and d, the association with medium to large system begin to become more evident. First, the mean profiles are alike, and second there is a presence of bright band. The development of these types of systems is followed by enhanced ice particles concentration at higher altitudes in the initial stage. Subsequently, in the mature stage the ice particles begin to fall and melt at the o C isotherm, which is evident in stratiform profile by the appearance of the bright band. In the later stage, decay, the profile shows the maximum reflectivities below km. For long duration MCS, lifetime above hours, we only have its initial and decay profile due to small matched observations. Apparently, it follows the same behavior as observed previously in Figures b. 3.3 Growth ratio The growth ratio is an index comparable to the divergence of the cloud system at high levels, where high values are related to the transport of large amounts of mass upward, and consequently strong vertical development. In our study, we compute this ratio in the early stages of the MCS development, since it can be related to the duration of the convective systems, as suggested by Machado et al., 199. The expression below defines this index: 1 AreaT AreaT 1 G = x, [1/hour] Area DT MCS ( media) Figures 3a and 3c show the mean vertical profile while Figures 3b and 3d present the cumulative surface rainfall distribution for two different initial growth ratio classes for both convective and stratiform rain pixels. Figure 3a presents the lifecycle evolution of CS with initial growth rate smaller than * -3 /hour. Based in the discussions above it is expected that these CSs will have shorter lifecycle than those CSs having larger initial growth rate. We can see in this figure that CS follows a typical lifecycle with small development in the initiation (mainly in the bright band) a larger increase in the hydrometeors in the mature stage, followed by a decrease in the concentration of the hydrometeors in all levels in the dissipation stage. Figure 3c shows the CS having larger initial growth rate [(-5)* -3 /hour]. These CSs present more 39

5 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, intense precipitation, which is coherent with the hypothesis that these CSs have longer lifecycle. In the initiation stage we can observe a large amount of precipitation in all levels followed by a significant increase in the middle levels in the mature stage. The stratiform rain portion, we can see a decrease of the bright band in the lower levels, probably due the large production of hydrometeors in the middle levels and the increase in the cloud cover area. In the dissipation stage the convective fraction collapses in the middle levels and the stratiform rain increases in the lower levels. 3. Split During the development of MCS, some of them arise from spontaneous generation and others by split. In the later generation a new CS is developed by the separation of the cores. In this type of CS, we only analyze the initial development, in order to understand differences that are characteristic of this situation. Therefore, we compare the initial profiles observed by both spontaneous and split generation as a function of radius and lifetime duration. Figures a and b present the mean convective rain profile for spontaneous and split generation as a function of radius and lifetime, while Figures c and d show the stratiform rain fraction. It is evident from Figure a that split generation CSs are stronger in all sizes, and for lifetime duration, Figure b, is the same except for system longer than hours. In summary, for small MCS (<5 km), the bright band is not so evident during the spontaneous generation, while for split it is explicit but not so strong. This difference might show the effect of small short life systems that produce ice particles in updrafts (spontaneous), while for split it shows the presence of snow and ice particle aloft produced by the mature stage of the main MCS. For the medium systems (5- km), there is higher concentration of ice particles for the spontaneous generation and higher at the surface for split generation. In the stratiform fraction, the spontaneous generation systems are stronger, which is consistent with the higher concentration of ice particles. In the case of large systems, the split generation systems are stronger than the spontaneous until km height. This effect might be associated with the large amount of ice particles that are aloft. 3.5 Merge The last part of this section concentrates in the MCS created by merge with other systems. In this particular case, we pay attention only at the decay development. For comparisons, we present the mean decay profiles of MCS for spontaneous and merge generation. Figures 5a and 5b present, the convective rain mean profiles as a function of size and lifetime duration while Figures 5c and 5d are for stratiform rain fraction. Most of the convective profiles show that during the spontaneous generation the MCS are stronger than merge generation, for both size and lifetime duration. In another hand, the stratiform part shows the contrary. This effect might show that the collapse of precipitating systems are more vigorous because the increase of ice particles that are falling, which is evident due to the increase of the bright band. In Figures 5a and 5b, the small systems show similar profiles, where small differences are observed near the surface and above km. The high concentration of ice particles in the spontaneous generation systems is evident by the increase of the bright band in the stratiform region, while for the merge generation heavier particles might not suffer the same melting effect of the first systems. For medium systems, more liquid water and ice content is observed in the spontaneous generation systems, but the stratiform region shows an intensification of the bright band for the merge systems. Therefore, the larger particles that might be associated with reasonable updrafts in the spontaneous systems cause the lower melting, while more small ice particles begin to melt in the merge systems. In the large systems, the convective rain fraction is stronger for the spontaneous system than the merge systems, and it is inverted to the stratiform part. Once again, the dense particles and the larger vertical movement in such clouds might play a strong role in the intensification of the convective and stratiform rain fraction. Figures 5b and 5d present the MCS as function of lifetime duration. As shown in section 3., the correspondent size and lifetime duration are not applied due to the small sample size. For short time 391

6 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, systems (< h), the convective fraction of the spontaneous generation is stronger than the merge system, which in the stratiform fraction is the contrary. It seems that these short-lived spontaneous systems are more active (large updrafts and ice particles), while the merge systems display a larger portion of stratiform rain produced by snow. Medium to longer time duration systems (-h) also shows the same effect presented before, for both convective and stratiform rain fraction. Finally, the long time duration systems show differences in the ice concentration, where in the convective fraction it is stronger in the spontaneous generation and in the stratiform for the merge generation.. Conclusion This study presented for the first time an inspection in the vertical structure of the precipitation observed in the Mesoscale convective systems observed in the Amazon basin as a function of radius, lifetime duration, growth ratio and life cycle stage. These results would be extended in a near future to a larger period to obtain a better representation both physically and statistically. Additionally, this study developed a methodology to inspect the vertical structure of the MCS by combining measurements of the Tropical Rainfall Measuring Mission Precipitation Radar and the GOES- satellite. During our analyses, we obtained 33 matched convective systems. The analyses of the MCS as function of radius revealed that as the system increase in size the amount of liquid water content and ice content increase, as well its vertical development. Similar results are found as a function of lifetime duration, but not so evident since the time intervals are not correspondent to the size investigated. In the growth rate index, the small systems, lower than * -3 /hour, present their most development in their mature stage. In another hand, the strong systems, (-5)* -3 /hour, present their most intense development during the initial stage. The split generation convective systems present more intense vertical structure than the spontaneous generation. This effect might be linked to the nature of its formation, since these systems are generated by a separation of the cores that are associated in the mature stage. Consequently, they have the presence of large vertical movements and ice particles aloft. The merge generation systems are weaker than the spontaneous generation during its decay life cycle. Apparently, the union of different cells contributes to dilute the strength of these systems. Therefore, a large portion of stratiform rain and evaporation (different air characteristics) might be responsible to the decrease in the intensification when compared to the spontaneous generation convective systems. 5. References Awaka, J., T. Iguchi, H. Kumagai, and K. Okamoto, 1997: Rain type classification algorithm for TRMM precipitation radar. Proceedings of the IEEE 1997 Int. Geosc. R. Sens. Symp., August 3-, Singapore, pp Awaka, J., T. Iguchi, and K. Okamoto, 199: Early results on rain type classification by the Tropical Rainfall Measuring Mission (TRMM) precipitation radar, Proc. th URSI Commission F Open Symp., Aveiro, Portugal, Chen S. S., R. A. Houze and B. E. Mapes, 199. Multiscale variability of deep convection in relation to large-scale circulation in TOGA COARE. J. Atmos. Sci., 53, 13, 19. Cotton W. R.and R. A. Anthes, 199. Storm and cloud dynamics. Academic Press, pp. Hodges, K. I., and C. D. Thorncroft, 1997: Distribution and statistics of African mesoscale convective weather systems based on the ISCCP METEOSAT imagery. Mon. Wea. Rev., 15,

7 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, Houze, Cloud dynamics. Academic Press, 573 pp. Iguchi T, R. Meneghini, J. Awaka, T. Kozu, K. Okamoto, : Rain profiling algorithm for TRMM precipitation radar data. Remote Sensing and Appl. Earth, Atmos. Oceans, vol. 5, 5, pp Kummerow, C., W. Barnes, T. Kozu, J. Shiue, and J. Simpson, 199: The Tropical Rainfall Measuring Mission (TRMM) sensor package. J. Atmos. Ocean. Tech., vol. 15, 3, pp Laurent, H. L.A.T. Machado, C.A. Morales, : Characteristics of the Amazonian mesoscale convective systems observed from satellite and radar during the WETAMC/LBA experiment. In press at J. Geophys. Res. Machado, L. A. T., W. B. Rossow, R. L. Guedes, and A. W. Walker, 199: Life cycle variations of mesoscale convective systems over the Americas. Mon. Wea. Rev., 1, Maddox, R. A., 19: Mesoscale convective complexes. Bull. Amer. Meteor. Soc., 1, Mapes, B. E., and R. A. Houze, 1993: Cloud clusters and superclusters over the oceanic warm pool. Mon. Wea. Rev., 11, Mathon V. and H. Laurent, 1. Life cycle of the Sahelian mesoscale convective cloud systems. Quart. J. Roy. Meteo. Soc., in press. Silva Dias, M.A.F., S. Rutledge, P. Kabat, P. Silva Dias, C. Nobre, G. Fisch, H. Dolman, E. Zipser, M. Garstang, A. Manzi, J. Fuentes H. Rocha, J. Marengo, A. Plana-Fattori, L. Sá, R. Alavalá, M. Andreae, P. Artaxo, 1: Clouds and rain processes in a biosphere atmosphere interaction context in the Amazon region. In press at J. Geophys. Res Simpson J., R. F. Adler, G. R. North, 199. A proposed Tropical Rainfall Measuring Mission (TRMM) satellite. Bull. Amer. Meteor. Soc., 9, 7-5. Steiner, M., R.A. Houze, and S.E. Yuter, 1995: Climatological characterization of three-dimensional storm structure from operation radar and rain gauge data, J. Appl. Meteor., 3, Velasco I. and J. M. Fritsch, 197. Mesoscale convective complexes in the Americas. J. Geophys. Res., 9,

8 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, a) b) Reflectivity Factor Life Cycle For MCS with Radius < 5 km ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure 1a and 1b. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS with radius -5 km for initial, mature and decaying life cycle stage 39

9 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, c) d) Reflectivity Factor Life Cycle For MCS with Radius 5- km ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure 1c and 1d. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS with radius 5- km for initial, mature and decaying life cycle stage 395

10 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, e) f) Reflectivity Factor Life Cycle For MCS with Radius > km ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure 1e and 1f. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS with radius greater than km for initial, mature and decaying life cycle stage 39

11 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, a) b) Reflectivity Factor Life Cycle For MCS < h ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure a and b. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS with lifetime lower than hours for initial, mature and decaying life cycle stage 397

12 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, c) d) Reflectivity Factor Life Cycle For MCS between - h ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure c and d. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS with lifetime between - hours for initial, mature and decaying life cycle stage 39

13 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, e) f) Reflectivity Factor Life Cycle For MCS > h ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure e and f. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS with lifetime greater than hours for initial, mature and decaying life cycle stage 399

14 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, a) b) Reflectivity Factor Life Cycle For MCS with Growth Rate -/hour ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay MCS Cumulative Rainfall Distribution Cumulative Frequency (%) Rainfall Rate (mm/h) Initial Mature Decay Figure 3a and 3b. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS as a function of growth ratio index (-x -3 /h) for initial, mature and decaying life cycle stage 33

15 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, c) d) Reflectivity Factor Life Cycle For MCS with Growth Rate -5/hour MCS Cumulative Rainfall Distribution Cumulative Frequency (%) ST - Initial CV - Initial ST - Mature CV - Mature ST - Decay CV - Decay Rainfall Rate (mm/h) Initial Mature Decay Figure 3c and 3d. Mean vertical radar reflective profile and cumulative rainfall distribution for MCS as a function of growth ratio index (-5x -3 /h) for initial, mature and decaying life cycle stage 331

16 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, a) b) Initial Stage for Spontaneous and Split MCS Mean Convective Rain Profile Spontaneous (-5km) Split (-5km) Spontaneous (5-km) Split (5-km) Spontaneous (>km) Split (>km) Initial Stage for Spontaneous and Split MCS Mean Convective Rain Profile Spontaneous (-h) Split (-h) Spontaneous (-h) Split (-h) Spontaneous (>h) Split (>h) Figures a and b. Mean convective rainfall vertical radar reflective profile for MCS with spontaneous generation and split generation as a function of size and lifetime duration during initial stages. 33

17 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, c) d) Initial Stage for Spontaneous and Split MCS Mean Stratiform Rain Profile Spontaneous (-5km) Split (-5km) Spontaneous (5-km) Split (5-km) Spontaneous (>km) Split (>km) Initial Stage for Spontaneous and Split MCS Mean Stratiform Rain Profile Spontaneous (-h) Split (-h) Spontaneous (-h) Split (-h) Spontaneous (>h) Split (>h) Figures c and d. Mean stratiform rainfall vertical radar reflective profile for MCS with spontaneous generation and split generation as a function of size and lifetime duration during initial stages. 333

18 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, a) b) Decay Stage for Spontaneous and Merge MCS Mean Convective Rain Profile Spontaneous (-5km) Merge (-5km) Spontaneous (5-km) Merge (5-km) Spontaneous (>km) Merge (>km) Decay Stage for Spontaneous and Merge MCS Mean Convective Rain Profile Spontaneous (-h) Merge (-h)l Spontaneous (-h) Merge (-h) Spontaneous (>h) Merge (>h) Figures 5a and 5b. Mean convective rainfall vertical radar reflective profile for MCS with spontaneous generation and merge generation as a function of size and lifetime duration during decay stages. 33

19 XII Congresso Brasileiro de Meteorologia, Foz de Iguaçu-PR, c) d) Decay Stage for Spontaneous and Merge MCS Mean Stratiform Rain Profile Spontaneous (-5km) Merge (-5km) Spontaneous (5-km) Merge (5-km) Spontaneous (>km) Merge (>km) Decay Stage for Spontaneous and Merge MCS Mean Stratiform Rain Profile Spontaneous (-h) Merge (-h) Spontaneous (-h) Merge (-h) Spontaneous (>h) Merge (>h) Figures 5c and 5d. Mean stratiform rainfall vertical radar reflective profile for MCS with spontaneous generation and merge generation as a function of size and lifetime duration during decay stages. 335