Presentation on theme: "Updates on NOAA MM5 Assessment Where we left off Buoy assessment Temperature problems Solar radiation assessment Z T simulation Analysis nudging Where."— Presentation transcript:
Updates on NOAA MM5 Assessment Where we left off Buoy assessment Temperature problems Solar radiation assessment Z T simulation Analysis nudging Where next?
Surface T & Td Summary Offshore and in Bay Area model has warm bias As air parcels move inland, warm T bias decreases and eventually disappears, Td moist bias increases As air parcels move inland, cold daytime bias increases CV has too small of an diurnal cycle in T CV has too moist Td’s Decreasing soil moisture will decrease cold daytime bias, increase diurnal range, and reduce Td bias
Solar Radiation Summary MM5 does a pretty good job of getting solar radiation correct. If anything, tends to over-predict solar radiation. To double check, ran simulation with cloud absorption turned off – little difference.
Z 0T Simulation MM5 default has Z 0T = Z 0M, but it should have Z 0T < Z 0M Z 0T = Z 0M exp[-kC (R e* ) 1/2 ] where R e* = Z 0M u * /μ
Summary Off-shore winds look reasonable, no significant speed bias. Directions good except last 1-2 days, with model winds too northerly. Surface T & Td and RASS assessments show: –Off-shore temps too warm due to lack of strong marine layer in the model. –In-valley surface T and Td biases become progressively cool and moist the further inland parcels go –model has cool bias to at least 700m AGL, and too small an amplitude to diurnal cycle Solar radiation is not source of in-valley temperature errors. New Z T formulation only improves Td, not T. Most likely that in-valley temperature errors are caused by land-surface model and/or too much soil moisture Analysis nudging run likely gives best winds so far. Will it give better ozone predictions?
Simulation Status Two additional analysis nudging simulations completed, not yet analysed –36 km grid, all levels except surface –36 km grid, all levels including surface Simulations planned –Reduced soil moisture (will it cause too much inflow through Bay Area?) –Alternate Z T formulations –Analysis nudging on 12 km grid –Combined analysis/obs nudging (with vertical spreading of obs)