Sunday, July 17, 2011
2011 Hurricane season:NASA’s TRMM Satellite Sees a Well-Organized, Major Typhoon Songda
0 comments Posted by Jeff adams at 8:56 PM
Typhoon Songda was east of the Philippines when the Tropical Rainfall Measuring Mission (TRMM) satellite had an early evening view on May 25, 2011 at 0903 UTC (05:03 EDT) and saw good organization within the storm and heavy rainfall. Songda has intensified into a major typhoon as it tracks parallel to the east coast of the northern Philippines, spawning warnings.
Both TRMM’s Microwave Imager (TMI) and Precipitation Radar (PR) instruments were used to provide the rainfall analysis. TRMM’s TMI had the best coverage of rainfall with Songda and showed well organized bands of moderate to heavy rainfall converging into the typhoon. TRMM is managed by both NASA and the Japanese Space Agency, JAXA.
Infrared imagery from the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua satellite showed an eye about 12 nautical miles wide and strong convection surrounding the eye on all sides. Songda intensified over the over the last 12 hours because of very warm sea surface temperatures between 30 and 31 Celsius, and low wind shear.
At 1500 UTC (11 a.m. EDT) on May 25, Songda’s maximum sustained winds were near 105 knots (120 mph/194 kmh) making it a Category Three Typhoon on the Saffir-Simpson scale. Sondga was located about 385 nautical miles east-southeast of Manila, Philippines and is now moving northwestward near 5 knots (6 mph/9 kmh). Yesterday it was moving to the west-northwest, so the curving northward has already begun.
Songda is predicted to become a very powerful category 4 super typhoon with wind speeds peaking at 125 knots (143 mph/231 kmh) as it passes to the northeast of the Philippines. By Friday, the current forecast track takes Songda’s center very close to the island with Kadena Air Base in the Northwestern Pacific Ocean.
read more
Tuesday, June 28, 2011
ATLANTIC
* A tropical wave moving west-northwestward into the Bay of Campeche is bringing disorganized but locally heavy showers and thunderstorms to the Yucatan Peninsula, southeast Mexico, and parts of Central America.
* This system could organize some on Tuesday or Wednesday as it moves through the Bay of Campeche and the shearing winds aloft relax, but may only at best become a tropical depression.
* Any developing tropical low and associated heavy rainfall will quickly move into northeast Mexico midweek and beyond.
* Southernmost Texas could see an increase in shower and thunderstorm activity.
Tuesday, June 07, 2011
Landsat 5 Satellite Sees Tornado Track near Sturbridge, Massachusetts
0 comments Posted by Jeff adams at 9:49 PM
The Thematic Mapper on the Landsat 5 satellite captured this natural-color image on June 5, 2011. This image shows part of the tornado track, including damage in Sturbridge. According to the Boston Globe, Massachusetts state police reported a tornado on the ground in Sturbridge at 5:22 p.m. The tornado was spotted on the Interstate 84 exit, and cars were overturned.
The Boston Globe reported that the Massachusetts governor declared a state of emergency and ordered National Guard troops to assist with cleanup efforts. Tornadoes on June 1 killed at least four residents of the state, as well as reducing homes, schools, and churches to rubble.
The Landsat Program is a series of Earth-observing satellite missions jointly managed by NASA and the U.S. Geological Survey. Since 1972, Landsat satellites have collected information about Earth from space. This science, known as remote sensing, has matured with the Landsat Program.
Thursday, June 02, 2011
This blog presents a data-rich view of climate and a discussion of how that data fits together into the scientists' current picture of our changing climate. But there's a great deal that we don't know about the future of Earth's climate and how climate change will affect humans.
Climate scientists often discuss "abrupt climate change," which includes the possibility of "tipping points" in the Earth's climate. Climate appears to have several states in which it is relatively stable over long periods of time. But when climate moves between those states, it can do so quickly (geologically speaking), in hundreds of years and even, in a handful of cases, in only a few decades. These rapid 'state changes' are what scientists mean by abrupt climate change. They are much more common at regional scales than at the global scale, but can be global. State changes have triggers, or tipping points. In what's probably the single largest uncertainty in climate science, scientists don't have much confidence that they know what those triggers are.
Below is an explanation of just a few other important uncertainties about climate change. This list isn't exhaustive. It is intended to illustrate the kinds of questions that scientists still ask about climate.
1. Solar Irradiance.
The sun has a well-known 11-year irradiance cycle that produces about .1% variation in output.1 Solar irradiance has been measured by satellite daily since the late 1970s, and this known solar cycle is incorporated into climate models. There is some evidence from proxy measurements-sunspot counts going back centuries, measurements from ancient trees, and others-that solar output varies over longer periods of time, too. While there is currently no evidence of a trend in solar output over the past half century, because there are no direct observations of solar output prior to the 1970s, climate scientists do not have much confidence that they understand longer-term solar changes. A number of U.S. and international spacecraft study the sun.
2. Aerosols, dust, smoke, and soot.
These come from both human and natural sources. They also have very different effects on climate. Sulfate aerosols, which result from burning coal, biomass, and volcanic eruptions, tend to cool the Earth. Increasing industrial emissions of sulfates is believed to have caused a cooling trend in the Northern Hemisphere from the 1940s to the 1970s. But other kinds of particles have the opposite effect. The global distribution of aerosols has only been tracked for about a decade from the ground and from satellites, but those measurements cannot yet reliably distinguish between types of particulates. So aerosol forcing is another substantial uncertainty in predictions of future climate.
