Landsats Aff

Refugees – UQ – Forecasts fail

In Figure 13, we note significant total population as the area affected by flood is densely populated. We try to understand population behavior and response to a mandatory evacuation order. Studies show that the State of Louisiana preference for advanced notification time of minimum 72 hours, the longest time in the country (some states have a requirement of advanced notification of 12 hours) for Category 5 hurricane (Wolshon et al, 2001). Current forecasts are not precise enough to give a reliable notification of 72 hours, and in practice the order was given about one day in advance. Previous studies also established evacuation plans and procedures and presented possible problems of the so called low mobility groups. The number of people without access to transportation in New Orleans is about 25-30 percent of the population. Moreover, destitute, elderly, prisoners, infirm and tourists contribute to the low mobility group. The problem was addressed by emergent management agencies to provided buses for the evacuation of low mobility groups. Earlier reports and experience of Katrina showed that New Orleans did not have the adequate supply of busses to transport all low mobility people (Wolshon, 2001).

In order to make efficient use of geographic information collected prior to or during humanitarian operations, the data should be stored and analyzed in a GIS. This requires that the data are geo-referenced, and ideally in a standardized format, so that they can be swiftly uploaded to the GIS. Satellite images can all be delivered with geographic coordinates for referencing when purchased through a data provider. However, the geometric accuracy of the data and rectified end-products may vary. This accuracy depends on how the geo-referencing was carried out, as well as the quality and number of ground control points used. If e.g. only satellite-orbit characteristics were used, the accuracy may vary from less than one pixel (a pixel is the smallest image-element, here defined to be the same as the spatial resolution of the image), to several pixels. If several known ground control points are used to reference the image, e.g. collected by relief-staff in the field using Global Positioning System (GPS) hand-held receivers, the accuracy normally is less than one pixel. Thus, satellite images should be geo-referenced according to the application and level of accuracy the information managers need, large area overviews of e.g. geo-locating damaged infrastructure in war torn areas or detailed refugee camp planning. The values of the acquired data signals must of course also be accurate in order to be used in decision-making processes. If an area is classified as deforested, then this image-derived information must be true. This type of accuracy is related to technical parameters, such as radiometric and spectral accuracy and will not be further described here, as that would be a highly technical discussion. The fact is, though, that most satellite sensors used by UN humanitarian organizations have been tested for many years and data analysis algorithms have been verified. One should nevertheless be aware of that satellite images consist of information collected from 400 to 36,000 km above the earth’s surface, and several parameters, such as haze and on-the-ground meteorological conditions may affect the data sensed from space. That is why image processing, analyses and interpretation should be carried out by experts.

The Landsat satellites make loops around the earth and are constantly collecting images of the surface through the use of a variety of sensing devices. Since the beginning of the Landsat program in 1972, the images and data have been available to all countries around the world. Images are used to measure rain forest loss, assist with mapping, determine urban growth, and population change. The different Landsats each have different remote sensing equipment. Each sensing device records radiation from the surface of the earth in different bands of the electromagnetic spectrum. Landsat 7 has more sensing equipment than any other Landsat. It even includes a new panchromatic scanner with an impressive resolution of 15 meters (the highest resolution until Landsat 7 was 30m). This means that buildings or other objects which are 15 meters across will show up on the Landsat images. The Landsats orbit the earth from the north to south poles and vice versa. Landsat 7 completes a full orbit of the earth in about 99 minutes, allowing the satellite to achieve over 14 orbits per day. The satellites make a complete coverage of the earth every 16 days.

A new USGS publication – Rate, Trends, Causes, and Consequences of Urban Land-Use Change in the United States (Professional Paper 1726) – studies the change in land use associated with increasing urbanization and its impacts at local, regional, and national scales. Based on the broad view of satellite imagery, the twenty scientific contributions that make up the publication examine urban land change in the United States from many perspectives – historical, geographic, economic, and ecological. Together the analyses provide new insights into critical issues of concern for both science and society. “The knowledge of how and why urban land-use change occurs coupled with a projection of its direction and likely effect can be helpful in informing local, regional, and national decisions about land use,” said Barbara Ryan, Associate USGS Director for Geography. “These public decisions will not only shape communities, but will substantially affect citizens’ lives and livelihood, the economy, and the environment for years to come.” As part of its mission to describe and understand the Earth, the USGS systematically monitors land surface change by observing the Earth with remote sensing satellites, studies the connections between people and those changes with geographic analysis, and provides individuals and society with relevant science information they can use to manage the consequences of those changes.

In an article titled “Modeling the human invader in the United States,” USGS scientists Thomas Stohlgren, Catherine Jarnevich, and Chandra Giri modeled humans as an “invasive species” as they “spread” in the conterminous U.S. from 1992 to 2001. Using the Landsat-derived National Land Cover Data (NLCD) together with a modeling program they mapped urbanization. (An area the size of Massachusetts was urbanized during the nine-year period studied and agricultural lands and forests were most likely to be urbanized.) The model, called Maxent, predicts species spread based on environmental factors. The authors used Maxent to model and map human spread from 1992 to 2001 and then compared it to the Landsat NLCD information. Using selected environmental variables (temperature, humidity, elevation, slope, geology) the model was 92.5 percent accurate. Based on their model results the authors concluded that humans have a highly predictable urbanization or “spread” pattern based on the environmental drivers of topography (elevation and slope) and climate (temperature and humidity).

By the time the hurricane subsided, Katrina had claimed more than 1,800 human lives and caused roughly $125 billion in damages. As scientists and rescue organizations worked on the ground to prepare for the hurricane and assist in its wake, NASA provided data gathered from a series of Earth-observing satellites to help predict the hurricane's path and intensity. In the aftermath, NASA satellites also helped identify areas hardest hit. In this 3 1/2-minute video created by NASA-TV producer Jennifer Shoemaker at NASA's Goddard Space Flight Center in Greenbelt, Md., viewers will see many different kinds of data NASA satellites gathered about the storm. The video contains a sampling of the kinds of things NASA studies about hurricanes. Various additional data products are created in hurricane and post-hurricane research that are not depicted in the video.

The video opens with Atlantic Ocean sea surface temperatures data from an instrument called AMSR-E (Advanced Microwave Scanning Radiometer - Earth Observing System) that flies aboard NASA's Aqua satellite. Warm ocean waters (of 80 degrees Fahrenheit or warmer) provided energy to fuel the growing storm. Next, the MISR (Multi-angle Imaging SpectroRadiometer) instrument on NASA's Terra satellite captured the growth of cloud tops in the gathering storm. Just before landfall, the Tropical Rainfall Measuring Mission (TRMM) satellite data revealed "hot towers" hidden within the hurricane -- powerful thunderstorms that helped intensify Katrina. TRMM also captured data on rainfall amounts throughout the hurricane's lifecycle. Finally, the video shows Landsat satellite imagery of New Orleans before and during the flooding, as well as a more recent view of a city still rebuilding from the hurricane some five years later.

NASA not only launches shuttles and builds space stations, it also builds and operates our nation's satellites that observe and monitor the Earth. These satellites collect crucial global data on winds, ice and oceans. They help us forecast hurricanes, track the loss of Arctic sea ice and the rise of sea levels, and understand and prepare for climate changes. NASA's budget for science missions has declined 30 percent in the past six years, and that trend is expected to continue. As more dollars are reallocated to prepare for missions back to the moon and Mars, sophisticated new satellites to observe the Earth will be delayed, harming Earth sciences. The National Academy of Sciences has noted that the Landsat satellite system, which takes important measurements of global vegetation, is in its fourth decade of operation and could fail without a clear plan for continuation. The same is true for the QuikSCAT satellite, which provides critical wind data used in forecasting hurricanes and El Niño effects.