tag:blogger.com,1999:blog-6141980.post2485193166109519395..comments2024-03-20T12:28:35.004-05:00Comments on Nuit Blanche: SKA as an Atmosphere Monitoring Station ?Igorhttp://www.blogger.com/profile/17474880327699002140noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-6141980.post-42726096971886563092014-03-31T17:59:05.334-05:002014-03-31T17:59:05.334-05:00Hi njh and Igor,
As someone who works on the SKA ...Hi njh and Igor,<br /><br />As someone who works on the SKA and on one of its pathfinder instruments (MeerKAT), as well as on the DOME project advertising the postdoc position, I feel obliged to respond :-)<br /><br />Radio telescopes *do* operate during the day, even if it is just to make the optical astronomers jealous (although they have the last laugh when you see how weak astronomical radio signals are). The Sun is not that big a problem to first order as our typical dishes are only sensitive to a one-degree patch on the sky and they can avoid the Sun during observations. Some very sensitive observations might still need to remove a tiny contribution from the Sun by the appropriate modelling.<br /><br />A ballpark number for the solar energy received on the Earth's surface is 1 kW per square meter. A square kilometer would therefore receive 1 GW. Given that the Sun is only up half the time and blithely ignoring clouds and other inefficiencies we have the potential for a 500 MW power plant. While this is large for a solar plant, it is below average for a coal-fired plant. The project will also need substantial additional funding to turn it into a solar plant. Maybe an idea for when the SKA retires? :-)<br /><br />To comment on Igor's statement that normal operation of the SKA during daylight ought to provide some information on the atmosphere above it: this is true. The radio signals to be received by the SKA (during the day or night) will mostly be affected by disturbances in the ionosphere and to a lesser extent by water vapour in the troposphere. These (unwanted!) phase drifts and attenuations have to be modelled and calibrated out to obtain a clear image. This is typically done in conjunction with direct atmospheric measurements using GNSS satellites and water vapour radiometers.<br />Anonymoushttps://www.blogger.com/profile/14592358201716895063noreply@blogger.com