Anthony J. Wimmers

MIMIC: A New Approach to Visualizing Satellite Microwave Imagery of Tropical Cyclones

Satellite-based passive microwave imagery of tropical cyclones (TCs) is an invaluable resource for assessing the organization and evolution of convective structures in TCs when often no other comparable observations exist. However, the current constellation of low-Earth-orbiting environmental satellites that can effectively image TCs in the microwave range make only semirandom passes over TC targets, roughly every 3 - 6 h, but vary from less than 30 min to more than 25 h between passes. These irregular time gaps hamper the ability of analysts/forecasters to easily incorporate these data into a diagnosis of the state of the TC. To address this issue, we have developed a family of algorithms called Morphed Integrated Microwave Imagery at the Cooperative Institute for Meteorological Satellite Studies (MIMIC) to create synthetic “morphed” images that utilize the observed imagery to fill in the time gaps and present time-continuous animations of tropical cyclones and their environment. MIMIC-TC is a product th...

Aviation Applications for Satellite-Based Observations of Cloud Properties, Convection Initiation, In-Flight Icing, Turbulence, and Volcanic Ash

Abstract Advanced Satellite Aviation Weather Products (ASAP) was jointly initiated by the NASA Applied Sciences Program and the NASA Aviation Safety and Security Program in 2002. The initiative provides a valuable bridge for transitioning new and existing satellite information and products into Federal Aviation Administration (FAA) Aviation Weather Research Program (AWRP) efforts to increase the safety and efficiency of the airspace system. The ASAP project addresses hazards such as convective weather, turbulence (clear air and cloud induced), icing, and volcanic ash, and is particularly applicable in extending the monitoring of weather over data-sparse areas, such as the oceans and other observationally remote locations. ASAP research is conducted by scientists from NASA, the FAA AWRPs Product Development Teams (PDT), NOAA, and the academic research community. In this paper we provide a summary of activities since the inception of ASAP that emphasize the use of current-generation satellite technologies ...

Objectively Determining the Rotational Center of Tropical Cyclones in Passive Microwave Satellite Imagery

Abstract Precise center-fixing of tropical cyclones (TCs) is critical for operational forecasting, intensity estimation, and visualization. Current procedures are usually performed with manual input from a human analyst, using multispectral satellite imagery as the primary tools. While adequate in many cases, subjective interpretation can often lead to variance in the estimated center positions. In this paper an objective, robust algorithm is presented for resolving the rotational center of TCs: the Automated Rotational Center Hurricane Eye Retrieval (ARCHER). The algorithm finds the center of rotation using spirally oriented brightness temperature gradients in the TC banding patterns in combination with gradients along the ring-shaped edge of a possible eye. It is calibrated and validated using 85–92-GHz passive microwave imagery because of this frequency’s relative ubiquity in TC applications; however, similar versions of ARCHER are also shown to work effectively with other satellite imagery of TCs. In ...

Seamless Advective Blending of Total Precipitable Water Retrievals from Polar-Orbiting Satellites*

AbstractConventional methods of viewing and combining retrieved geophysical fields from polar-orbiting satellites often complicate the work of end users because of the erratic time differences between overpasses, the significant time gaps between elements of a composite image, or simply the different requirements for interpretation between contributing instruments. However, it is possible to mitigate these issues for any number of retrieved quantities in which the tracer lifetime exceeds the sampling time. This paper presents a method that uses “advective blending” to create high-fidelity composites of data from polar-orbiting satellites at high temporal resolution, including a characterization of error as a function of time gap between satellite overpasses. The method is especially effective for tracers with lifetimes of longer than 7 h. Examples are presented using microwave-based retrievals of total precipitable water (TPW) over the ocean, from the Cooperative Institute for Meteorological Satellite Stu...

Improvements in the Probabilistic Prediction of Tropical Cyclone Rapid Intensification with Passive Microwave Observations

AbstractThe probabilistic prediction of tropical cyclone (TC) rapid intensification (RI) in the Atlantic and eastern Pacific Ocean basins is examined here using a series of logistic regression models trained on environmental and infrared satellite-derived features. The environmental predictors are based on averaged values over a 24-h period following the forecast time. These models are compared against equivalent models enhanced with additional TC predictors created from passive satellite microwave imagery (MI). Leave-one-year-out cross validation on the developmental dataset shows that the inclusion of MI-based predictors yields more skillful RI models for a variety of RI and intensity thresholds. Compared with the baseline forecast skill of the non-MI-based RI models, the relative skill improvements from including MI-based predictors range from 10.6% to 44.9%. Using archived real-time data during the period 2004–13, evaluation of simulated real-time models is also carried out. Unlike in the model develo...

Advancements in Objective Multisatellite Tropical Cyclone Center Fixing

AbstractAn improved version of the Automated Rotational Center Hurricane Eye Retrieval (ARCHER) tropical cyclone (TC) center-fixing algorithm, introduced here as “ARCHER-2,” is presented with a characterization of its accuracy and precision and a comparison with alternative methods. The algorithm is calibrated for 37- and 85–92-GHz microwave imagers; geostationary imagery at visible, near-infrared, and longwave infrared window channels; and scatterometer ambiguities. In addition to a center fix, ARCHER-2 produces a quantitative estimate of expected error that can be used automatically or manually to evaluate the suitability of a result. The median center-fix error ranges from 24 (using scatterometer) to 49 (using infrared window) km relative to the National Hurricane Center best track. Multisatellite, multisensor results can also be used together to produce a TC-track estimate that selects from the best of all of the available imagery in the ancillary “ARCHER-Track” product. The median error of ARCHER-Tra...

Developing a Global Turbulence and Convection Nowcast and Forecast System

Turbulence is widely recognized as the leading cause of injuries to flight attendants and passengers on commercial air carriers. Turbulence encounters frequently occur in oceanic and remote regions where ground-based observations are sparse, making hazard characterization more difficult, and where current World Area Forecast System products provide only low temporal and spatial resolution depictions of potential hazards. This paper describes a new effort to develop a global diagnosis and forecast system that will augment and enhance international turbulence and convective SIGMETs and provide authoritative global turbulence data for the NextGen 4-D database. This fully automated system, modeled on the FAA’s Graphical Turbulence Guidance (GTG) and GTG Nowcast systems, will provide 3-D probabilistic turbulence nowcasts and forecasts globally above 10,000 feet MSL for 0-36 hour lead times, comprehensively addressing clear-air turbulence (CAT), mountain wave turbulence (MWT), and convectively-induced turbulence (CIT). The system will employ NCEP Global Forecast System model output and data from NASA and other national and international satellite assets to produce the CAT and MWT diagnoses based on both model-based turbulence diagnostics and satellite-based turbulence detection algorithms. The convective nowcast methodology makes use of GFS data and operational satellite data from GOES, Meteosat and MTSAT, and will be tuned and verified using data from NASA’s TRMM, Cloudsat and MODIS instruments. The convective nowcasts will be coupled with the GFS environmental information to assess the near-term likelihood of CIT. This paper presents an overview of the system elements and initial algorithm development results. Future work will perform additional development and verification using comparisons with automated quantitative in situ turbulence reports, AIREPs and AMDAR data. A real-time demonstration including a webbased display and cockpit uplinks is also planned.

3D-AQS, a Three-Dimensional Air Quality System

In 2006, we began a three-year project funded by the NASA Integrated Decisions Support program to develop a three-dimensional air quality system (3D-AQS). The focus of 3D-AQS is on the integration of aerosol-related NASA Earth Science Data into key air quality decision support systems used for air quality management, forecasting, and public health tracking. These will include the U.S. Environmental Protection Agency (EPA)s Air Quality System/AirQuest and AIRNow, Infusing satellite Data into Environmental Applications (IDEA) product, U.S. Air Quality weblog (Smog Blog) and the Regional East Atmospheric Lidar Mesonet (REALM). The project will result in greater accessibility of satellite and lidar datasets that, when used in conjunction with the ground-based particulate matter monitors, will enable monitoring across horizontal and vertical dimensions. Monitoring in multiple dimensions will enhance the air quality communitys ability to monitor and forecast the geospatial extent and transboundary transport of air pollutants, particularly fine particulate matter. This paper describes the concept of this multisensor system and gives current examples of the types of products that will result from it.