Daniel T. Lindsey

Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities

Most environmental satellite radiometers use solar reflectance information when it is available during the day but must resort at night to emission signals from infrared bands, which offer poor sensitivity to low-level clouds and surface features. A few sensors can take advantage of moonlight, but the inconsistent availability of the lunar source limits measurement utility. Here we show that the Day/Night Band (DNB) low-light visible sensor on the recently launched Suomi National Polar-orbiting Partnership (NPP) satellite has the unique ability to image cloud and surface features by way of reflected airglow, starlight, and zodiacal light illumination. Examples collected during new moon reveal not only meteorological and surface features, but also the direct emission of airglow structures in the mesosphere, including expansive regions of diffuse glow and wave patterns forced by tropospheric convection. The ability to leverage diffuse illumination sources for nocturnal environmental sensing applications extends the advantages of visible-light information to moonless nights.

The Untold Story of Pyrocumulonimbus

Wildfire is becoming the focus of increasing attention. It is now realized that changes in the occurrence frequency and intensity of wildfires has important significant consequences for a variety of important problems, including atmospheric change and safety in the urban–wildland interface. One important but poorly understood aspect of wildfire behavior—pyrocumulonimbus firestorm dynamics and atmospheric impact—has a curious history of theory and observation. The “pyroCb” is a fire-started or fire-augmented thunderstorm that in its most extreme manifestation injects huge abundances of smoke and other biomass-burning emissions into the lower stratosphere. The observed hemispheric spread of smoke and other biomass-burning emissions could have important climate consequences. PyroCbs have been spawned naturally and through anthropogenesis, and they are hypothesized as being part of the theoretical “Nuclear nuclear winter” work. However, direct attribution of the stratospheric aerosols to the pyroCb only occur...

First-Light Imagery from Suomi NPP VIIRS

The Suomi National Polar-Orbiting Partnership (NPP) satellite was launched on 28 October 2011, heralding the next generation of operational U.S. polar-orbiting satellites. It carries the Visible– Infrared Imaging Radiometer Suite (VIIRS), a 22-band visible/infrared sensor that combines many of the best aspects of the NOAA Advanced Very High Resolution Radiometer (AVHRR), the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS), and the National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. VIIRS has nearly all the capabilities of MODIS, but offers a wider swath width (3,000 versus 2,330 km) and much higher spatial resolution at swath edge. VIIRS also has a day/night band (DNB) that is sensitive to very low levels of visible light at night such as those produced by moonlight reflecting off low clouds, fog, dust, ash plumes, and snow cover. In addition, VIIRS detects light emissions from cities, ships, oil flares, and ...

The Great Colorado Flood of September 2013

AbstractDuring the second week of September 2013, a seasonally uncharacteristic weather pattern stalled over the Rocky Mountain Front Range region of northern Colorado bringing with it copious amounts of moisture from the Gulf of Mexico, Caribbean Sea, and the tropical eastern Pacific Ocean. This feed of moisture was funneled toward the east-facing mountain slopes through a series of mesoscale circulation features, resulting in several days of unusually widespread heavy rainfall over steep mountainous terrain. Catastrophic flooding ensued within several Front Range river systems that washed away highways, destroyed towns, isolated communities, necessitated days of airborne evacuations, and resulted in eight fatalities. The impacts from heavy rainfall and flooding were felt over a broad region of northern Colorado leading to 18 counties being designated as federal disaster areas and resulting in damages exceeding

An Evaluation of Five ARW-WRF Microphysics Schemes Using Synthetic GOES Imagery for an Atmospheric River Event Affecting the California Coast

2 billion (U.S. dollars). This study explores the meteorological and hydrological ingredients...

Lightning in Wildfire Smoke Plumes Observed in Colorado during Summer 2012

AbstractThe main purpose of the present study is to assess the value of synthetic satellite imagery as a tool for model evaluation performance in addition to more traditional approaches. For this purpose, synthetic GOES-10 imagery at 10.7 μm was produced using output from the Advanced Research Weather Research and Forecasting (ARW-WRF) numerical model. Use of synthetic imagery is a unique method to indirectly evaluate the performance of various microphysical schemes available within the ARW-WRF. In the present study, a simulation of an atmospheric river event that occurred on 30 December 2005 was used. The simulations were performed using the ARW-WRF numerical model with five different microphysical schemes [Lin, WRF single-moment 6 class (WSM6), Thompson, Schultz, and double-moment Morrison]. Synthetic imagery was created and scenes from the simulations were statistically compared with observations from the 10.7-μm band of the GOES-10 imager using a histogram-based technique. The results suggest that syn...

Fire Detection Using GOES Rapid Scan Imagery

AbstractPyrocumulus clouds above three Colorado wildfires (Hewlett Gulch, High Park, and Waldo Canyon; all during the summer of 2012) electrified and produced localized intracloud discharges whenever the smoke plumes grew above 10 km MSL (approximately −45°C). Vertical development occurred during periods of rapid wildfire growth, as indicated by the shortwave infrared channel on a geostationary satellite, as well as by incident reports. The lightning discharges were detected by a three-dimensional lightning mapping network. Based on Doppler and polarimetric radar observations, they likely were caused by ice-based electrification processes that did not involve significant amounts of high-density graupel. Plumes that did not feature significant amounts of radar-inferred ice at high altitudes did not produce lightning, which means lightning observations may assist in diagnosing pyrocumulus features that could affect the radiative characteristics and chemical composition of the upper troposphere. The lightnin...

GOES Climatology and Analysis of Thunderstorms with Enhanced 3.9-μm Reflectivity

Abstract This paper demonstrates the proper use of geostationary satellite imagery in wildland fire detection. The roles of both the visible and the 3.9-μm channels are emphasized. Case studies from June 2002 are presented to illustrate techniques that can be utilized in both the detection and short-range forecasting processes. The examples demonstrate that, when utilized correctly, the sensitivity of the shortwave infrared channel to subpixel heat sources can often result in detections that match the timelines of human observations. Finally, a derived satellite product that increases the detection rate of wildland fires from space is described.

Synthetic Satellite Imagery for Real-Time High-Resolution Model Evaluation

Abstract By combining observations from the Geostationary Operational Environmental Satellite (GOES) 3.9- and 10.7-μm channels, the reflected component of the 3.9-μm radiance can be isolated. In this paper, these 3.9-μm reflectivity measurements of thunderstorm tops are studied in terms of their climatological values and their utility in diagnosing cloud-top microphysical structure. These measurements provide information about internal thunderstorm processes, including updraft strength, and may be useful for severe weather nowcasting. Three years of summertime thunderstorm-top 3.9-μm reflectivity values are analyzed to produce maps of climatological means across the United States. Maxima occur in the high plains and Rocky Mountain regions, while lower values are observed over much of the eastern United States. A simple model is used to establish a relationship between 3.9-μm reflectivity and ice crystal size at cloud top. As the mean diameter of a cloud-top ice crystal distribution decreases, more solar r...

Assimilating synthetic GOES-R radiances in cloudy conditions using an ensemble-based method

AbstractOutput from a real-time high-resolution numerical model is used to generate synthetic infrared satellite imagery. It is shown that this imagery helps to characterize model-simulated large-scale precursors to the formation of deep-convective storms as well as the subsequent development of storm systems. A strategy for using this imagery in the forecasting of severe convective weather is presented. This strategy involves comparing model-simulated precursors to their observed counterparts to help anticipate model errors in the timing and location of storm formation, while using the simulated storm evolution as guidance.