R. Blakeslee - Academia.edu (original) (raw)

Papers by R. Blakeslee

ABSTRACT CHUVA is a Brazilian research program that is characterizing the main precipitating syst... more ABSTRACT CHUVA is a Brazilian research program that is characterizing the main precipitating systems observed in Brazil as a support for Global Precipitation Measurement (GPM) mission. CHUVA conducts a series of field campaigns in the time frame of 2010-2013 that sample raining systems from maritime to continental regime in polluted and clean environments. From November of 2011 through March of 2012, CHUVA is hosting a field program at Vale do Paraiba, southeast of Brazil, where NOAA and EUMETSAT deployed 12 LMA and 7 LINET antennas respectively to gather lightning measurements to support the development of algorithms that will be employed by GOES-R and Third Generation Meteosat satellites. Due to this opportunity, other lightning detection systems have been invited to participate in this campaign. As a result, for the first time it will be possible to gather coincident measurements from 10 different lightning detection technologies, i.e., a) VHF: LMA and TLS200 Vaisala; b) VLF: WWLLN, STARNET, Vaisala GLD360, WSI and ATDNet; c) VLF/LF: RINDAT, LINET; c) ELF/VLF/LF/VHF: Weather Bug. As each system uses different frequencies, detection (sky/ground waves or line of sight, electrical and magnetic fields) and methodology for location (TOA, ATD and interferometry) it is expect that each system observes different parts of the lightning flash. Thus taking the opportunity that LMA measures most of the lightning sources associated to all atmospheric discharges, this study will concentrate on describing what each technology measures/detects in respect to LMA source over selected thunderstorms.

Journal of the Atmospheric Sciences, 1979

Because the linear growth rates of baroclinic waves on realistic zonal flows are largest at relat... more Because the linear growth rates of baroclinic waves on realistic zonal flows are largest at relatively high zonal wavenumbers (e.g., 15), the observed peaks in the transient kinetic energy spectrum cannot be explained simply by peaks in the linear growth-rate spectrum. When the growth-rate spectrum is fairly flat, as suggested by recent studies, then as the waves evolve, the decrease

NASA Earth science research utilizes both spaceborne and airborne real time observations in the p... more NASA Earth science research utilizes both spaceborne and airborne real time observations in the planning and operations of its field campaigns. The coordination of air and space components is critical to achieve the goals and objectives and ensure the success of an experiment. Spaceborne imagery provides regular and continual coverage of the Earth and it is a significant component in all NASA field experiments. Real time visible and infrared geostationary images from GOES satellites and multi-spectral data from the many elements of the NASA suite of instruments aboard the TRMM, Terra, Aqua, Aura, and other NASA satellites have become norm. Similarly, the NASA Airborne Science Program draws upon a rich pool of instrumented aircraft. The NASA McDonnell Douglas DC-8, Lockheed P3 Orion, DeHavilland Twin Otter, King Air B200, Gulfstream-III are all staples of a NASA's well-stocked, versatile hangar. A key component in many field campaigns is coordinating the aircraft with satellite ...

Journal of Atmospheric and Oceanic Technology, 2000

Lightning data from the US National Lightning Detection Network (NLDN) are used to perform prelim... more Lightning data from the US National Lightning Detection Network (NLDN) are used to perform preliminary validation of the satellite-based Optical Transient Detector (OTD). Sensor precision, accuracy, detection efficiency, and biases of the deployed instrument are ...

Geophysical Research Letters, 1992

This report describes a transient luminosity observed at the altitude of the airglow l•[yer (abou... more This report describes a transient luminosity observed at the altitude of the airglow l•[yer (about 95 km) in coincidence with a lightning flash ir• a tropical oceanic thunderstorm directly beneath it. This event provides new evidence of direct coupling between lightning and ionospheric events. This luminous event in the ionpsphere was the only one of its kind observed during an examination of several thousand images of lightning recorded under suitable viewing conditions with Space Shuttle cameras. Several possible mechanisms and interpretations are dispussed briefly.

NASA CONFERENCE …, 1999

The Lightning Imaging Sensor (LIS) is a NASA Earth Observing System (EOS) instrument on the Tropi... more The Lightning Imaging Sensor (LIS) is a NASA Earth Observing System (EOS) instrument on the Tropical Rainfall Measuring Mission (TRMM) platform designed to acquire and investigate the distribution and variability of total lightning (i.e., cloud-to-ground and intracloud) between ±35 o in latitude. Since lightning is one of the responses of the atmosphere to thermodynamic and dynamic forcing, the LIS data is being used to detect deep convection without land-ocean bias, estimate the precipitation mass in the mixed phased region of thunderclouds, and differentiate storms with strong updrafts from those with weak vertical motion. Figure 3. An example of (a) LIS, (b) TMI, (c) VIRS, and (d) PR data for storms in East Texas and Louisiana on January 22, 1998 at 0412 UTC.

ABSTRACT This study evaluates the effectiveness of spectrophotometric measurements from space in ... more ABSTRACT This study evaluates the effectiveness of spectrophotometric measurements from space in revealing properties of lightning flashes. The multicolor optical waveform data obtained by FORMOSAT-2/ISUAL were analyzed in relation to the National Lightning Detection Network (NLDN), North Alabama Lightning Mapping Array (LMA). As of July 2011, we found six lightning events which were observed by ISUAL and North Alabama LMA. In two of these events, NLDN showed clear positive cloud-to-ground (CG) discharges with peak currents of +139.9 kA and +41.6 kA and, around that time, LMA showed continuous intra-cloud (IC) leader activities at 4-6 km altitudes. ISUAL also observed consistent optical waveforms of the IC and CG components and, interestingly, it was found that the blue/red spectral ratio clearly decreased by a factor of 1.5-2.5 at the time of CG discharges. Other four lightning events in which NLDN did not detect any CG discharges were also investigated, but such a feature was not found in any of these cases. These results suggest that the optical color of the CG component is more reddish than that of the IC component and we explain this as a result of more effective Rayleigh scattering in blue light emissions coming from lower-altitude light source. This finding suggests that spectral measurements could be a new useful technique to characterize ICs and CGs from space. In this presentation, we will also show results from lightning statistical analysis of ISUAL spectrophotometric data and ULF magnetic data.

We have built a system, Storm Airborne Monitor for Precipitation, Lightning, and Environment usin... more We have built a system, Storm Airborne Monitor for Precipitation, Lightning, and Environment using Intelligent Sensor Control (SAMPLE/ISC) for real-time data monitoring, payload control, and data recording. The basic system was successfully demonstrated during the Tropical Cloud System and Processes (TCSP) experiment in July 2005. It integrates innovative aircraft payload, communications, and data recording components with ground-based applications. The ground-based

Journal of the Atmospheric Sciences, 1979

Journal of Atmospheric and Oceanic Technology, 2000

Geophysical Research Letters, 1992

NASA CONFERENCE …, 1999