FIG 5 - uploaded by Edward J. Zipser
Content may be subject to copyright.
Diurnal cycle of the three most extreme categories (top 0.1%; Figs. 2 and 3) for each parameter separated by land and ocean PFs. There are not enough extreme events over oceans to use only the top two categories.
Source publication
The instruments on the Tropical Rainfall Measuring Mission (TRMM) satellite have been observing storms as well as rainfall since December 1997. This paper shows the results of a systematic search through seven full years of the TRMM database to find indicators of uncommonly intense storms. These include strong (> 40 dBZ) radar echoes extending to g...
Similar publications
Seventeen years of remotely sensed satellite mounted Lightning Imaging Sensor (LIS) data were used to determine the characteristics of lightning activities over Sri Lanka. From 1998 to 2014, there were 12.5 million lightning flashes over the land mass covered by Sri Lanka. There is an increasing trend in the intensity of lightning activities with 2...
Utilizing data from the Tropical Rainfall Measuring Mission (TRMM) satellite’s precipitation radar (PR) and lightning imaging sensor (LIS), this study explores the spatiotemporal distributions of thunderstorm and lightning structures over the Qinghai–Tibet Plateau (QTP), an aspect that has not been explored previously. The structural aspects are cr...
The most intense thunderstorms on Earth were surveyed using the comprehensive meteorological instrumentation on the Tropical Rainfall Measuring Mission (TRMM) satellite. Expansive land‐based Mesoscale Convective Systems (MCSs) were consistently identified among the Earth's most intense thunderstorms, with their organization into many convective cel...
Plain Language Summary
When extreme precipitation occurs, one will easily connect it to intense storms such as those producing numerous lightning flashes. However, some rainstorms display little severe signatures, therefore, they are even more challenging from the monitoring or nowcasting point of view. This study investigates the warm‐season extre...
Measurements provided by Next Generation Weather Radar and operational thunderstorm monitoring instruments at the Kennedy Space Center and the Air Force Eastern Range have been examined to determine the initial electrical development of 13 isolated, air mass thunderstorms. The same instruments were used to examine the surface potential gradient pri...
Citations
... The exact reflectivity value adopted for the echo-top calculation varies because of the different saturation values for each wavelength and the radars' minimum sensitivity thus offering different insights about the lofting of hydrometeors on convection. Reflectivity values for convective proxies range from 0 and 10 dBZ for CPR (e.g., Stephens and Wood 2007;Luo et al. 2008;Takahashi and Luo 2014) and 30 to 40 dBZ for TRMM (e.g., Zipser et al. 2006;Houze Jr. et al. 2015) and GPM's KuPR (e.g., Skofronick-Jackson et al. 2018). The broad result of the echo-top convective proxies between missions paints a consistent picture of stronger convection being generally located over land, with more frequent locations of intense convection over hotspots like Central Africa, North-Central Argentina and the central United States (Zipser et al. 2006;Houze Jr. et al. 2015;Takahashi and Luo 2014). ...
... Reflectivity values for convective proxies range from 0 and 10 dBZ for CPR (e.g., Stephens and Wood 2007;Luo et al. 2008;Takahashi and Luo 2014) and 30 to 40 dBZ for TRMM (e.g., Zipser et al. 2006;Houze Jr. et al. 2015) and GPM's KuPR (e.g., Skofronick-Jackson et al. 2018). The broad result of the echo-top convective proxies between missions paints a consistent picture of stronger convection being generally located over land, with more frequent locations of intense convection over hotspots like Central Africa, North-Central Argentina and the central United States (Zipser et al. 2006;Houze Jr. et al. 2015;Takahashi and Luo 2014). The differences in echo-top heights of the different radar systems, not yet researched in detail, also offers potential insights into processes associated with detraining ice in upper levels of storms. ...
... The differences arise from the echo-top height locations, the anvil characteristics and the depth at which the shorter wavelengths become affected by attenuation and multiple scattering. Contextualizing these two cases of very strong convection in the broader convective proxy literature, both cases would be used in CPR studies of deep convective clouds with 10 dBZ echo-tops exceeding 10 km (e.g., Takahashi et al. 2023).Meanwhile from the KuPR perspective, the MCS on 12 Jun 2018 would be within the top 0.33% of storms and the more isolated storm from 08 May 2019 would be within the top 0.03% within the Zipser et al. (2006) framework (see Fig. 6 in Skofronick-Jackson et al. 2018). In the University of Washington classifications both storms are considered the Deep and Wide classification (Houze Jr. et al. 2007), but note the part sampled by the three radars for the MCS case was likely not the most intense part of the storm (stronger GMI brightness temperature deficits were found outside the DPR swath; not shown). ...
Global numerical weather models are starting to resolve atmospheric moist convection which comes with a critical need for observational constraints. One avenue for such constraints is spaceborne radar which tend to operate at three wavelengths, Ku-, Ka- and W-band. Many studies of deep convection in the past have primarily leveraged Ku-band because it is less affected by attenuation and multiple scattering. However, future spaceborne radar missions might not contain a Ku-band radar and thus considering the view of convection from Ka-band or W-band compared to the Ku-band would be useful. This study examines a coincident dataset between the Global Precipitation Measurement (GPM) Mission and CloudSat as well as the entire GPM record to compare convective characteristics across various wavelengths within deep convection. We find that W-band reflectivity (Z) tends to maximize near the Ku-band defined echo-top while Ka-band often maximizes 4-5 km below. The height of the maximum Z above the melting level for W-band and Ka-band do not linearly relate to the Ku-band maximum. However, using the full GPM record the Ka-band 30 dBZ echo-tops can be linearly related to the Ku-band 40 dBZ echo-top with an $R^2$ of 0.62 and a root mean squared error of about 1 km. The spatial distribution of echo-tops from Ka-band corresponds well to the Ku-band echo-tops, highlighting regions of relatively large ice water path. This paper suggests that Ka-band only missions, like NASA's Investigation for Convective Updrafts, should be able to characterize global convection in a similar manner to a Ku-band system.
... The prevailing monsoonal flows transport abundant moisture to the BoB, creating an environment conducive to the initiation and organization of deep convection (e.g., Romatschke & Houze, 2011;Shige et al., 2017;Xie et al., 2006). Zipser et al. (2006) and Romatschke et al. (2010) used the precipitation radar onboard the Tropical Rainfall Measuring Mission (TRMM) satellite to study the monsoonal convective systems over the BoB. They found that the majority of warmseason precipitation over the BoB is contributed by wide cloud features with broad stratiform areas (>50,000 km 2 ) embedded by several deep convective cores. ...
Previous observational studies have indicated that mesoscale convective systems (MCSs) contribute the majority of precipitation over the Bay of Bengal (BoB) during the summer monsoon season, yet their initiation and propagation remain incompletely understood. To fill this knowledge gap, we conducted a comprehensive study using a combination of 20-year satellite observations, MCS tracking, reanalysis data, and a theoretical linear model. Satellite observations reveal clear diurnal propagation signals of MCS initiation frequency and rainfall from the west coast of the BoB toward the central BoB, with the MCS rainfall propagating slightly slower than the MCS initiation frequency. Global reanalysis data indicates a strong association between the offshore-propagating MCS initiation frequency/rainfall and diurnal low-level wind perturbations, implying the potential role of gravity waves. To verify the hypothesis, we developed a 2-D linear model that can be driven by realistic meteorological fields from reanalysis. The linear model realistically reproduces the characteristics of offshore-propagating diurnal wind perturbations. The wind perturbations, as well as the offshore propagation signals of MCS initiation frequency and rainfall, are associated with diurnal gravity waves emitted from the coastal regions, which in turn are caused by the diurnal land-sea thermal contrast. The ambient wind speed and vertical wind shear play crucial roles in modulating the timing, propagation, and amplitude of diurnal gravity waves. Using the linear model and satellite observations, we further show that the stronger monsoonal flows lead to faster offshore propagation of diurnal gravity waves, which subsequently control the offshore propagation signals of MCS initiation and rainfall.
... For analysis of convective intensity, defined in this paper as radar reflectivity intensity related to hydrometeors as a proxy for convective updraft intensity (e.g., Heymsfield et al., 2010;Ni et al., 2019;Zipser et al., 2006;Zipser & Lutz, 1994), all APR-3 Ku-band reflectivity profiles for an individual case were binned into two-dimensional (2-D) histograms with 5-dBZ and 0.5-km intervals. Reflectivity was binned from 10 dBZ to 60 dBZ, and height bins extend from 1.5 to 8 km, so as to omit potentially spurious near-surface data Sadowy et al., 2003) and provide a uniform upper layer altitude cap to allow for case intercomparison. ...
Deep tropical oceanic convection (TOC) is a prevailing component of the tropical atmosphere and plays a significant role in modulating global weather and climate. Despite its importance, prediction challenges remain, partly attributed to a lack of understanding of how TOC relates to its near‐storm environments. Prior studies suggest location‐dependent relationships between TOC structure and associated environments, necessitating targeted regional studies. The NASA 2017 Convective Processes Experiment (CPEX) and 2021 CPEX—Aerosols & Winds (CPEX‐AW) field campaigns collected high‐resolution measurements of convective storms and their environments in the Gulf of Mexico, Caribbean, and western Atlantic basins, providing a rare opportunity to investigate near‐storm environmental relationships with 3‐D TOC structure where in situ non‐tropical cyclone‐related deep TOC research is comparatively lacking. Collocated CPEX and CPEX‐AW airborne observations from the multi‐wavelength Airborne Precipitation Radar, Doppler Aerosol Wind Lidar, and dropsondes revealed large near‐storm environmental variability across TOC of similar convective type (i.e., isolated, organized) and within individual convective systems. However, trends still emerged amongst the large environmental variability. Horizontal TOC structure was most consistently linked to planetary boundary layer and mid‐tropospheric near‐storm environments, with organized TOC being associated with generally greater relative humidity (RH) and vertical speed shear than isolated TOC. TOC intensity was linked to upper tropospheric (i.e., above melting level) near‐storm environments, with isolated TOC intensity most consistently associated with upper tropospheric CAPE and organized TOC intensity associated with upper tropospheric RH. Mesoscale low‐level convergence was also linked to greater organized TOC intensity, motivating further research using these unique data sets.
... The maximum height of 40 dBZ echo-top (maxHt_40dBZ) is used to characterize convective intensity of the individual CCs, following previous studies (i.e., Hamada et al., 2014Hamada et al., , 2015Zipser et al., 2006). Convective intensity of a CC with maxHt_40dBZ above 9 km is considered as "intense convection" , as such maxHt_40dBZ values indicate presence of strong updrafts in the convective system to lift large precipitation particles (graupel or hail) up to above the 22°C level (Yu22). ...
In this study, the Extreme Hourly Precipitation Areas (EHPAs) of three extreme levels (i.e., between the 95th and 99th percentiles, between the 99th and 99.9th percentiles, beyond the 99.9th percentile) in the Pearl River Delta over South China are identified; then the related events and associated Convective Cores (CCs) are tracked, and their macro‐and‐microphysical characteristics are analyzed using multi‐year dual‐polarization radar observations. Results show that >90% of EHPAs are smaller than 10 km², and 65%–75% of EHPA events last only one hour. They tend to be more localized and persist longer with increasing hourly‐precipitation extremity. The EHPAs overlap with the CCs during 50%–64% of the EHPAs' life span. Their occurrence frequencies are nearly quadrupled after the monsoon onset over South China Sea (SCS), with a major (secondary) peak at about 1400 LST (0600 LST) in the diurnal variations. The CCs are non‐linear shaped with about 65% being meso‐γ‐scale and embedded within mostly meso‐β or α‐scale 20 dBZ regions. The CCs generally contain active warm‐rain processes and about 70% possess moderate‐to‐intense mixed‐phase microphysical processes. The ratios of ice water path to liquid water path are about 0.37, and coalescence dominates (about 68%) the liquid‐phase processes. The average size of raindrop is slightly larger than the “maritime‐like” regime and the average concentration is much higher than the “continental‐like” regime. These CCs' characteristics roughly resemble those of the convection producing extreme instantaneous precipitation, except for a larger horizontal scale and less evident variations with the increasing hourly‐precipitation extremity.
... Ku-band detections derived separately (Kubota et al. 2014 Jiang et al. 2013) and other precipitation systems (e.g., thunderstorms) (Zipser et al. 2006). The ocean surface has low emissivity, which interferes with the identification of convection. ...
The mesoscale features of 400 tropical cyclones (TCs) over the western North Pacific during 2014–2021 were investigated through Global Precipitation Measurement Microwave Imager and Dual-frequency Precipitation Radar observations. An improved algorithm has been developed to identify active mesoscale convective systems (MCSs) in TCs. These MCSs are continuous systems with active precipitation, exhibiting deep convection, and only account for a small portion of the precipitating pixels within a TC. This study highlights the evolving characteristics of MCSs and their precipitation features in TCs of different intensity categories. The development and evolution of active MCSs in TCs are influenced by the degree of organization of the system. During the tropical depression stage, the maintenance of MCSs relies heavily on substantial convective precipitation pixels, especially deep convection. The convection exhibits a high echo top height and significant ice scattering feature. As the TC intensity increases, MCSs are more likely to be in a mature state where convective precipitation is no longer as crucial for their development. This transition leads to a decrease in the proportion and the 20-dBZ echo top height of deep convection in both the inner- and outer-core region. The proportion of stratiform precipitation increases, ultimately resulting in an expansion in the MCS size and an increase in the PCTs of MCSs. By elucidating these phenomena, this study deepens our understanding of the structure and precipitation features of TCs, providing insights into the unique characteristics of MCS development that differ from the synoptic-scale features of TC development.
... Additionally, the passage of cold fronts associated with extratropical cyclones serves as an important source of convective activity in the URB region ( [1]). Furthermore, subtropical South America is recognized as one of the world's most active regions for severe convective storms ( [17,18]). These convective storms can also generate high precipitation rates, leading to extreme events. ...
This study analyzes the spatial distribution and trends in five extreme daily rainfall indices in the Uruguay River Basin (URB) from 1993 to 2022 using the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) dataset. The main findings reveal a predominantly positive trend in heavy precipitation (R95p) and extreme precipitation (R99p) events over the mid URB, while a negative trend is observed in the upper and low URB. Significant trends in the frequency of heavy and extreme rainfall were observed during autumn (MAM), with positive trends across most of the mid and upper URB and negative trends in the low URB. In the upper URB, negative trends in the frequency of extremes were also found during spring (SON) and summer (DJF). Overall, there was a reduction in the number of consecutive wet days (CWD), particularly significant in the upper URB and the northern half of the mid URB. Additionally, the upper URB experienced an overall increase in the duration of consecutive dry days (CDD).
... OTs were analyzed over southeastern South America (SESA), which is known to have some of the deepest convective storms on Earth (Liu et al., 2020;Zipser et al., 2006). The Remote Sensing of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observations-Clouds, Aerosol, and Complex Terrain Interactions (RELAMPAGO-CACTI) field campaign took place in SESA, with most observations taken from 1 November 2018-31 January 2019 Varble et al., 2021). ...
Overshooting tops (OTs) are manifestations of deep convective updrafts that extend above the tropopause into the stratosphere. They can induce dynamic perturbations and result in irreversible transport of aerosols, water vapor and other mass from the troposphere into the stratosphere, thereby impacting the chemical composition and radiative processes of the stratosphere. These and other effects of OTs depend on their characteristics such as depth and area, which are understood to connect to mid‐tropospheric updraft speed and width, respectively. Less understood is how static stability in the lower stratosphere (LS) potentially modulates these OT–updraft connections, thus motivating the current study. Here, LS static stability and observed OT characteristics are quantified and compared using a combination of reanalysis data, observed rawinsonde data and geostationary satellite data. A weak to moderate relationship between OT depth and LS lapse rate and Brunt‐Väisälä frequency (N²) (R = 0.38, −0.37, respectively) is found, implying that OT depth is reduced with an increasingly stable LS. In contrast, a weak relationship (R = −0.03, 0.03, respectively) is found between OT area and LS static stability, implying that OT area is controlled primarily by mid to upper tropospheric updraft area. OT duration has a weak relationship to LS lapse rate and N² (R = 0.02, −0.02, respectively). These relationships may be useful in interpreting mid‐ and low‐level storm dynamics from satellite‐observed characteristics of OTs in near real‐time.
... Particularly concerning the regions of interest, the Southern region ( Figure 6 e) exhibits notable disparities in ice content compared to other regions. Several studies consider the subtropical region of the South Atlantic (which includes the South brazilian region) as one of the areas on the planet most affected by severe convective events [33][34][35][36][37]. Such events involve clouds with deep vertical development, reaching very low temperatures, and consequently, they form a substantial amount of ice. ...
Intense rainfall events frequently occur in Brazil, often leading to rapid flooding. Despite their recurrence, there is a notable lack of sub-daily studies in the country. This research aims to assess patterns related to the structure and microphysics of clouds driving intense rainfall in Brazil, resulting in high accumulations within 1 hour. Employing a 40 mm/h threshold and validation criteria, 83 events were selected for study, observed by both single and dual-polarization radars. Contoured Frequency by Altitude Diagrams (CFADs) of reflectivity, Vertical Integrated Liquid (VIL), and Vertical Integrated Ice (VII) are employed to scrutinize the vertical cloud characteristics in each region. To address limitations arising from the absence of polarimetric coverage in some events, three case studies focusing on polarimetric variables are included. A fourth case study enhances the overall understanding of these events, emphasizing the underexplored nature of short-term intense rainfall studies in Brazil. Results reveal that the generating system significantly influences the rainfall pattern, especially in the Southern, Southeastern, and Central-Western regions. Regional CFADs unveil primary convective columns with 40-50 dBZ reflectivity, extending to approximately 6 km. The microphysical analysis highlights the rapid structural intensification, challenging the event predictability and the issuance of timely specific warnings.
... The pattern of monthly rainfall erosivity (Fig. 2) followed the typical seasonality of rainfall 38,39 : high monthly mean daily rainfall values were observed in July and August globally and in the Northern Hemisphere and in January and February in the Southern Hemisphere. Zipser et al. 40 also reported high-intensity storms, notably in June-August (Northern Hemisphere) and December-February and March-May (Southern Hemisphere). The latitudinal profile of a zonally averaged monthly rainfall erosivity (Fig. 3a) provides a near-global view of the intra-annual variability. ...
... Table S2). The seasonal EDs suggest that intense rainstorms dominantly occurred during June-August in the Northern Hemisphere, but were bimodally distributed between December-February and March-May in the Southern Hemisphere, in good agreement with the results of Zipser et al. 40 . ...
Modeling monthly rainfall erosivity is vital to the optimization of measures to control soil erosion. Rain gauge data combined with satellite observations can aid in enhancing rainfall erosivity estimations. Here, we presented a framework which utilized Geographically Weighted Regression approach to model global monthly rainfall erosivity. The framework integrates long-term (2001–2020) mean annual rainfall erosivity estimates from IMERG (Global Precipitation Measurement (GPM) mission’s Integrated Multi-satellitE Retrievals for GPM) with station data from GloREDa (Global Rainfall Erosivity Database, n = 3,286 stations). The merged mean annual rainfall erosivity was disaggregated into mean monthly values based on monthly rainfall erosivity fractions derived from the original IMERG data. Global mean monthly rainfall erosivity was distinctly seasonal; erosivity peaked at ~ 200 MJ mm ha−1 h−1 month−1 in June–August over the Northern Hemisphere and ~ 700 MJ mm ha−1 h−1 month−1 in December–February over the Southern Hemisphere, contributing to over 60% of the annual rainfall erosivity over large areas in each hemisphere. Rainfall erosivity was ~ 4 times higher during the most erosive months than the least erosive months (December–February and June–August in the Northern and Southern Hemisphere, respectively). The latitudinal distributions of monthly and seasonal rainfall erosivity were highly heterogeneous, with the tropics showing the greatest erosivity. The intra-annual variability of monthly rainfall erosivity was particularly high within 10–30° latitude in both hemispheres. The monthly rainfall erosivity maps can be used for improving spatiotemporal modeling of soil erosion and planning of soil conservation measures.
... Many studies have recognized Southern South America (south of 15°S; Fig. 1) as a worldwide hot spot for strong deep moist convection (e.g.: Zipser et al. 2006;Romatschke and Houze 2010;Rasmussen and Houze 2011;Rasmussen et al. 2014;Prein and Holland 2018;Ribeiro and Bosart 2018;Bruick et al. 2019;Zhou et al. 2021). Environmental conditions here often favor the development of organized storms capable of producing severe weather hazards (i.e., hail, strong wind gusts, tornadoes). ...
Despite Southern South America being recognized as a hotspot for deep convective storms, little is known about the socio-environmental impacts of high impact weather (HIW) events. Although there have been past efforts to collect severe weather reports in the region, they have been highly fragmented among and within countries, sharing no common protocol, and limited to a particular phenomenon, a very specific region or a short period of time.
There is a pressing need for a more comprehensive understanding of the present risks linked to HIW events, specifically deep convective storms, on a global scale as well as their variability and potential future evolution in the context of climate change. A database of high-quality and systematic HIW reports and associated socio-environmental impacts is essential to understand the regional atmospheric conditions leading to hazardous weather, to quantify its predictability and to build robust early warning systems.
To tackle this problem and following successful initiatives in other regions of the world, researchers, national weather service members, and weather enthusiasts from Argentina, Brazil, Chile, Paraguay and Uruguay have embarked on a multi-national collaboration to generate a standardized database of reports of HIW events principally associated with convective storms and their socio-environmental impacts in South America. The goal of this paper is to describe this unprecedented initiative over the region, to summarize first results and to discuss the potential applications of this collaboration.
