Stratospheric Ozone Depletion Study

In the stratosphere high above the Western Pacific Ocean this summer a consortium of scientists will study the how black soot, greenhouse gases, and water vapor are impacting Earth's ozone layer, according to a report on Huliq.com and confirmed by NOAA reports.

Huliq states that the gathering place is Costa Rica. The dates are July 2 through August 15. The site and season are 8 to 13 miles above the Western Pacific Ocean during the tropical rainy season. The goal is to gain understanding of key processes related to climate change, the stratospheric ozone layer, and global warming.

According to the National Oceanic and Atmospheric Administration (NOAA), the targeted zone is the gateway to the stratosphere. It is tropical tropopause transition layer (TTL). Deep convection can sometimes penetrate the TTL to reach the stratosphere. Further, the upwards motion of air within the TTL may loft materials across the TTL (above the tropics) into the stratosphere. This explains why water vapor and gases can move across the TTL into the stratosphere. The stratosphere can be adversely effected by anything that changes the physics of the TTL or the chemicals that are in the TTL.

This tropical tropopause transition layer experiment is called Tropical Composition, Cloud and Climate Coupling (TC4). The NOAA, Cooperative Institute for Research in Environmental Sciences (CIRES), and Earth System Research Lab (ESRL) are combining efforts in the TC4 experiment.The aim, as stated by Huliq, is to collect data pertaining to black carbon particles, ozone, water vapor, and particle composition. Measurements will also be taken of air pressure and temperature. The experiment will use a wide array of instruments.

The TC4 mission will investigate the structure, properties and processes in the tropical Western Pacific atmosphere. The mission will also provide data with which to verify data collected from A-train satellite observations that studies the TTL. Since the troposphere at times bears clouds, A-train data collecting is at times obscured.

As NOAA states, TC4 has two parts, one in Costa Rica and one later in Guam. Three levels of tropospheric atmosphere will be investigated. For this purpose, three aircraft will be used, NASA's DC-8, ER-2 and WB-57, which will be used for low-altitude, mid-altitude, and high-altitude investigations, respectively.

According to Huliq, among the investigators in the high-altitude investigation are David Fahey (NOAA), James Elkins (ESRL), and Holger Vömel (CIRES). They will fly instruments aboard NASA's high-altitude WB-57 aircraft, reports Huliq. Fahey will use his instruments to measure black carbon to detect how black carbon effects clouds and how clouds are able to remove it from the atmosphere.

Elkins will measure 20 gases including methane, HCFC-22, peroxyacytyl nitrate (PAN), and methyl iodide. Chloroflurocarbons and their substitutes will be studied because they are human-made ozone-depleting compounds, or greenhouse gases. Methyl iodide requires study because an iodine atom has the potential, depending on the lifetime of the gas, to attack the stratospheric ozone layer 200 times more effectively than a chlorine atom as in a chloroflurocarbon. Elkins told Huliq, "Until recently, we thought oceans were the only important source of methyl iodide. Now we know the Amazon can be a big source...We now have to look into what it means for the ozone layer."

Holger Vömel will measure water vapor and ozone in the stratosphere above the transition layer with instrumented balloons launched from San Jose airport. Water vapor, oddly enough, is the most powerful and most prevalent greenhouse gas, according to the report in Huliq. In the lower stratosphere, the target for the instrumented balloons, the air is much drier than above Earth's surface.

Among the instruments flown aboard NASA's WB-57 high-altitude aircraft will be six water vapor instruments, Huliq reports. The measurements of these instruments will verify measurements from the A-train satellite, just as the balloon instruments will help clear up discrepancies between various water vapor measuring instruments. The confirmations and corroborations will provide accuracy checks for satellite instruments. As Fahey told Huliq, "Everyone wants to know how accurate the satellites are...It's incredibly important."

NOAA, "TC4 Home Page." NOAA Earth Science project Office. URL: http://cloud1.arc.nasa.gov/tc4/

"harminka, "Scientists to search tropical skies." Huliq:Breaking News. URL: http://www.huliq.com/25852/scientists-to-search-tropical-skies

According to the NOAA, the chemical, dynamic, and physical processes at work in the upper troposphere and the tropopause transitional layer are not completely understood. NOAA further states: Identifying the key processes in this region is essential for progress on issues involving global climate change, stratospheric ozone depletion, and tropospheric chemistry.