High Frequency Weather Forecasts

Last updated: Wed, Dec 04, 08:00:00 UT

Ronald J Maddalena (Retired) and Larry Morgan
Green Bank Observatory, Green Bank, WV

All High-Frequency Overview Plots

• Relative Efficiencies using Limits  -- Limits*Effs/EffMin = LimitEff*LimitTrack*EffAtmos*EffTrack*EffSurf/EffMin
• The total score by which the DSS judges which projects will make the most efficient use of telescope time.
• Efficiencies without Limits -- Effs = EffAtm*EffTrack*EffSurf
• Shows observing efficiency (Effs = EffAtm*EffTrack*EffSurf) without applying the DSS judgments for both the frequency-dependent stringency (EffMin) and the limits of when a project will become futile (LimitEff and LimitTrack).
• Efficiencies from Atmospheric Opacities -- EffAtmos
• Shows the degradation in the the part of efficiency that arises from the atmosphere, relative to the best possible conditions for Green Bank.
• Efficiencies from Tracking Errors -- EffTrack
• Shows the degradation in the the part of efficiency that arises from tracking and pointing errors due to winds and due to poorer telescope pointing performance during daytime observing, relative to nighttime observing.
• Efficiencies from Surface Errors -- EffSurf
• Shows the degradation in the the part of efficiency that arises from surface errors due to daytime observing, relative to nighttime observing.
• Minimum Relative Efficiencies -- EffMin
• Indicates the minimum observing efficiency (Effs) for which the DSS judges that the science for a project will become futile.
• Limits on Relative Efficiency -- LimitEff
• Indicates the penalty a project incurs for having an efficiency (Effs) below EffMin.
• Limits on Tracking Efficiency -- LimitTrack
• Depicts a boolean that indicates when the estimated tracking and pointing errors will be large enough that the DSS judges that the science for a project will be futile.
• Cloud Coverage and Conditions Unsuitable for Continuum Observing
• Shows the criteria for continuum observations, which have an additional scoring factors based upon cloud coverage, the atmospheric contributions to system temperature, and the IR irradiance from the sky.
• Original Overview for REST and Winds (Pizza Plot)
• Displayed for historical purposes only

Explanation: The total score by which the DSS judges which projects will make the most efficient use of telescope time.

Explanation: Shows observing efficiency (Effs = EffAtm*EffTrack*EffSurf) without applying the DSS judgments for both the frequency-dependent stringency (EffMin) and the limits of when a project will become futile (LimitEff and LimitTrack).

Explanation: Shows the degradation in the the part of efficiency that arises from the atmosphere, relative to the best possible conditions for Green Bank.

Explanation: Shows the degradation in the the part of efficiency that arises from tracking and pointing errors due to winds and due to poorer telescope pointing performance during daytime observing, relative to nighttime observing.

Explanation: Shows the degradation in the the part of efficiency that arises from surface errors due to daytime observing, relative to nighttime observing.

Explanation: Indicates the minimum observing efficiency (Effs) for which the DSS judges that the science for a project will become futile.

Explanation: Indicates the penalty a project incurs for having an efficiency (Effs) below EffMin.

Explanation: Depicts a boolean that indicates when the estimated tracking and pointing errors will be large enough that the DSS judges that the science for a project will be futile.

Explanation: Shows the criteria for continuum observations, which have an additional scoring factors based upon cloud coverage, the atmospheric contributions to system temperature, and the IR irradiance from the sky. Various colors codes depict different aspects of cloud coverage and other criteria for scheduling continuum projects.  In short, the times when conditions are best for continuum observing are those where blue extends from the top to the bottom of the figure.  Any shade of white, cyan, or magenta indicate less than perfect continuum conditions.

Dark Magenta: Unsuitable for Mustang (Daytime or high winds) Medium Magenta: Unsuitable for Mustang (Atmos Tsys > 50 K) Light Magenta: Suitable for some Mustang (Atmos Tsys is 35-50 K ) Cyan Unsuitable for all others systems (LWd > 300 W/m2)

RESTs Good Winds Usable Winds Winds Too High < 1.41 < 2 at 22 GHz < 2, all but 22 GHz >= 2

Explanation: Plot provided mostly for historical purposes The suggested wind limits use the PTCS recommendations for good (<5% gain fluctuations) or usable (<10% gain fluctuations) conditions or the telescope's stow wind speeds.  The suggested RESTs limit for most frequencies is 1.41, which implies one will need twice the integration time as would be needed on the best of days. REST>2 indicates needing more than 4x as much integration and are usually not recommended. The suggested RESTs limits for 22 GHz is 2 since so little good weather is available at this frequency.