David J. Travis

University of Wisconsin - Whitewater | UWW · Department of Geography and Geology

Contrail statistical prediction methods are often location specific. To take advantage of the fact that the upper-tropospheric (UT) meteorological conditions that favor "clear-sky outbreaks" of persisting contrails, or contrail favored areas (CFAs), tend to be synoptic in scale, a visual UT-map technique to hindcast CFAs has been developed and test...

Although removing the pixels covered by contrails and their shadows and restoring the missing information at the locations in remotely sensed imagery are important to understand contrails' effects on climate change, there are no such studies in the current literature. This study investigates the restoration of the missing information of the pixels...

The cirrus-level condensation trails (contrails) produced by jet aircraft often occur as sub-regional-scale 'outbreaks of multiple contrails, suggested as contributing to post similar to 1965 climate trends in parts of the US and Europe. Several previously-developed, satellite-image based contrail spatial inventories for the conterminous US (CONUS)...

Contrails are important in understanding how aviation potentially affects climate change. The commonly used methods for detecting contrails usually only consider the spectral information of the image. This study focuses on introducing an object-based method for detecting contrails in AVHRR images. An object-based method utilizes not only the spectr...

Although geographers are highly visible in research into contemporary climate changes accompanying greenhouse gas increases (“global warming”), a relatively little explored component by them is the impact of aviation. This contrasts with the atmospheric science community of cloud physicists, chemists, and numerical modelers, who use geographic tool...

The presence of clouds and their shadows in remotely sensed images limits their potential uses for extracting information. The commonly used methods for replacing clouded pixels by land cover reflection estimates usually yield poor results if the images being combined exhibit radical differences in target radiance due, for example, to large date se...

In Part I of this observational study inquiring into the relative influences of "top down" synoptic atmospheric conditions and "bottom up" land surface mesoscale conditions in deep convection for the humid lowlands of the Midwest U.S. Central Corn Belt (CCB), the composite atmospheric environments for afternoon and evening periods of convection (CV...

In the Midwest U. S. Corn Belt, the 1999 and 2000 summer seasons (15 June-5 September) expressed contrasting spatial patterns and magnitudes of precipitation (1999: dry; 2000: normal to moist). Distinct from the numerical modeling approach often used in studies of land surface-climate interactions, a "synoptic climatological" (i.e., stratified comp...

The cirrus-level "condensation trails" (contrails) produced by jet aircraft are considered to influence surface climate and its recent changes. To reveal the synoptic atmospheric environments typically associated with multiple co-occurrences of contrails occurring in otherwise clear or partly cloudy skies (outbreaks) for the United States, and ulti...

In the United States, the dramatic increase in jet fuel usage and kilometers flown has led to speculation of a similar increase in jet contrails. However, contrail occurrence depends heavily upon the meteorological conditions near cruising altitudes (i.e. the tropopause, 10–12 km altitude). This study reports a contrail mid-season contemporary clim...

Using appropriate techniques to fill the data gaps in SLC-off ETM+ imagery may enable more scientific use of the data. The local linear histogram-matching technique chosen by USGS has limitations if the scenes being combined exhibit high temporal variability and radical differences in target radiance due, for example, to the presence of clouds. Thi...

In regions where jet air traffic is most abundant, condensation trails (contrails) may substantially increase the high cloud coverage, potentially affecting climate. This is particularly so when atmospheric conditions support prolonged persistence of contrails, which results in their occurrence in clusters, or ``outbreaks'', thus, allowing them to...

Specific studies about the stable isotope composition (18O/16O and D/H) of atmospheric icy conglomerations are still scarce. The present work offers, for the first time, a very detailed analysis of oxygen and hydrogen isotopic signatures of unusually large ice conglomerations, or “megacryometeors”, that fell to the ground in Spain during January 20...

The grounding of all commercial aircraft within U.S. airspace for the 3-day period following the 11 September 2001 terrorist attacks provides a unique opportunity to study the potential role of jet aircraft contrails in climate. Contrails are most similar to natural cirrus clouds due to their high altitude and strong ability to efficiently reduce o...

In a recent study facilitated by the 3-day grounding of all U.S. commercial aircraft following the September 11th, 2001 terrorist attacks we showed that jet contrails are reducing the diurnal temperature range (DTR) at Earth's surface. We attributed this DTR reduction to the unusual ability of contrails to efficiently reduce both the surface receip...

Human-induced changes to the landscape of the U.S. Midwest have produced a patchwork of agricultural land bordering forest remnants. In the warm season, the differences in boundary-layer characteristics (temperature, moisture, aerodynamic roughness) created by these strong contrasts in land cover can generate mesoscale circulations during synoptic...

The potential of condensation trails (contrails) from jet aircraft to affect regional-scale surface temperatures has been debated for years, but was difficult to verify until an opportunity arose as a result of the three-day grounding of all commercial aircraft in the United States in the aftermath of the terrorist attacks on 11 September 2001. Her...

The potential of condensation trails (contrails) from jet aircraft to affect regional-scale surface temperatures has been debated for years, but was difficult to verify until an opportunity arose as a result of the three-day grounding of all commercial aircraft in the United States in the aftermath of the terrorist attacks on 11 September 2001. Her...

Human-induced land cover modifications impact the planetary boundary layer's (PBL) thermal and moisture regimes on mesoscales. We investigate the association of croplands, forest, and the crop-forest “boundary” (CFB) with convective-cloud development (timing, amount) for three target areas (TAs) in the U.S. Midwest “Corn Belt”, during the summer se...

The possible contribution of jet aircraft condensation trails (contrails) to recent observed increases in high cloudiness constitutes a potentially important human effect on climate that has received relatively little attention. Very high resolution (0.6 km) thermal-infrared imagery from the Defense Meteorological Satellite Program polar orbiters,...

A topic of considerable interest today is whether condensation trails generated by the growing number of passenger and other jet aircraft (Figure 1) alter Earth's radiation balance enough to influence regional weather and global climate [e.g., Rind et al. , 1996]. While any global influences of contrails have yet to be detected, a number of studies...

The increases in total cloud amount documented for large regions during the latter half of the twentieth century have focused attention on the potential contribution from jet condensation trails (contrails). The environmental conditions that favor contrail formation and persistence are not well understood primarily due to the limited number of empi...

Land-surface-atmosphere interactions for the 1988 summer drought in the Mid-west USA are studied at climatic scales (104 km2; >5 days) using polar orbiter satellite radiance information on vegetation activity and cloud conditions. The emphasis is on documenting the occurrences of ‘organized’ land-cover types and cumulus convection, and evaluating t...

Jet condensation trails (contrails) are suspected to be an important contributor to the increase in high clouds that has been recognized since the middle of this century. Contrails can persist and spread in large groups, or "outbreaks", when occurring in a unique range of atmospheric conditions. During these situations they can significantly modify...

Storms late in the winter produced the greatest reductions in ring widths. For the two loblolly sites, ice storm severity increased the explained variance by 0.11 (0.35-0.46) and by 0.10 (0.39-0.49), respectively. Each severe ice storm occurrence was associated with a large negative residual. Radial growth reduction appears to be confined to the im...