Technological Improvements: Radiosonde Part III

       Last week, I talked about how long the radiosonde flight lasts, how data is screened, and how wind direction and speed was determined from the flight path of the radiosonde. This week, as I mentioned in the previous article, I will talk about some of the improvements in the data collection process has improved forecasting.

       

      Due to government spending, budget cuts, and a limited money supply, the NWS is forced to slowly cut down on its work force and the amount of money it spends on forecasting and saving lives. If no changes were made to this, all kinds of weather would kill thousands more than already are killed. One of the ways that the National Weather Service can make up for this, is through researching more modern and advanced technology in use for forecasting. Right now, radiosondes are sent up only a twice a day to receive upper air conditions and many other useful products for weather forecasting. The problem with this extremely inefficient system is that the atmosphere changes so quickly, that many factors can be missed. Take for instance on the day of a severe weather outbreak. Usually, the morning sounding will show almost no instability, due to the fact that the surface has not had time to heat from the sun. This will lead to extremely inaccurate calculations when trying to determine when the severe thunderstorms, which could end up meaning the difference between several hundred to over a million lives at stake (depending on the area). During the 1990's, to obtain meaningful wind measurements at all times of the day, the National Weather Service and the National Severe Storms Laboratory set up network of wind instruments called wind profilers across the Central Plains. These wind profilers are similar to Doppler Radars, except the fact that their parabolic dishes which sent out the microwaves are mounted vertically. As long as the microwaves which are sent out into the vertical can be scattered from dust particles or other particulate matter (including water vapor), wind speed and direction can be determined at many different levels of the atmosphere. Three other dishes are mounted at different angles to help determine the wind speed and direction. The NWS thought that this would give a much greater advantage to severe storm forecasters, as it allowed them to accurately determine wind shear throughout the low levels of the atmosphere. Then, in 2004, the wind profilers were cut out of the National Weather Service budget, and now they are funded by other means. The data is available online at several websites. Its data has other uses to, some of which have been described by other meteorologists. They claim that it may be possible to calculate the upper level wind, pressure, and temperature patterns just by knowing the wind speed and direction at a certain height. This could give a great advantage to many meteorologists, as long as these profilers are not shut down. There have been several cases where profiler data has made a huge difference in the forecast, one of which happened during the infamous May 3, 1999 tornado outbreak near Oklahoma City. Because of the profiler in central New Mexico, forecasters determined that there was a jet streak that missed by the radiosondes. Jet streaks are known to cause strong upward motion and destabilization, which would definitely help initiate severe thunderstorms. Also, jet streaks can also strengthen the vertical wind shear, which causes thunderstorms to become more organized.

       There are other ways that upper air data is obtained, and one of them is through a system called AMDAR. AMDAR come from air planes who are flying at specific pressure levels. Usually, these planes are commerical flights as they usually fly in the upper troposphere. The onboard instruments measure temperature, wind, pressure and humidity. The data is then relayed to the World Meteorological Organization, which collects and disperses the data. This data is especially useful in Africa and the Middle East, where the countries have Weather Services that are not funded by the government, or the country is so poor, there is no weather service. Another way data is collected is through weather satellites. Not only can they detect wind speed and direction and most levels (through tracking cloud movement), but through their radiation detection systems, they can determine temperature and dew point levels throughout all levels of the atmosphere. This system was implemented with the Terra series of satellites in 1999. In October of 2011, NOAA's next generation of earth monitoring satellites, called Suomi NPP, were sent up into space. This new generation of satellites have much more advanced equipment, which could eventually make them more accurate then radiosondes themselves. Plus, atmospheric soundings and wind profiles can be computed for any airport location in the world, and at each and every hour. The one problem with GOES soundings (their proper name) is that they have really coarse resolution, which affects certain small scale features. This being resolved with the NPP satellites which not only have better resolution, but they can also determine data in the presence of clouds. This will greatly improve forecasting within the next 10 or even 20 years.

      Next week, I am going to write about my trip to the National Weather Service on June 12, 2012, and then the following week's article is going to be about the history of the National Weather Service and its future plans. Have a great week!