3 rd IPWG 2006: 1 RVL 2/14/2016 MIT Lincoln Laboratory Modeling Validation with NAST-M and a Cloud-Resolving Model at GHz This work was sponsored by the National Oceanic and Atmospheric Administration under contract FA C Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the United States Government. R.V. Leslie, L. J. Bickmeier, W. J. Blackwell, and F. W. Chen Contributions from C. Surussavadee, P. Rosenkranz, and D. Staelin (MIT RLE); Paul Bieringer and Jonathan Hurst (MIT LL) 3 rd International Precipitation Working Group Workshop Melbourne, Australia October 25, 2006

MIT Lincoln Laboratory 3 rd IPWG 2006: 2 RVL 2/14/2016 Outline Introduction: Reconciling models & measurements NAST-M instrument Numerical Weather Prediction (NWP) model Radiative transfer model & tuning Comparison of simulated data & observations Summary

MIT Lincoln Laboratory 3 rd IPWG 2006: 3 RVL 2/14/2016 Reconciliation of Models and Measurements Numerical Weather Prediction (NWP) Models –Given atmospheric state at t 0, predict atmospheric states at t 1, t 2, … Microphysical Electromagnetic Models –Given microphysical properties of precipitation (particle size/abundance of ice, liquid, hail, graupel, etc.) calculate radiative properties (scattering and absorption of microwave radiation) High-Resolution Microwave Radiance Measurements –NAST-M aircraft instrument Goal: Optimization of the radiative transfer model through aircraft validation Radiative Transfer NWP Modeling Observations

MIT Lincoln Laboratory 3 rd IPWG 2006: 4 RVL 2/14/2016 NPOESS Aircraft Sounding Testbed - Microwave (NAST-M)  Cruising altitude: ~17-20 km  Cross-track scanning  Scan angle: -65º to 65º  Swath width of ~100 km  7.5º antenna beam width (FWHM)  2.5 km nadir footprint diameter Developed by MIT RLE

MIT Lincoln Laboratory 3 rd IPWG 2006: 5 RVL 2/14/2016 Atmospheric Opacity at Microwave and Millimeter–Wave Frequencies  Four Spectrometers  24 Oxygen Channels  6 Water Vapor Channels  Millimeter-wave Propagation Model  Standard Atmosphere O2O2 O2O2 O2O2 H2OH2O

MIT Lincoln Laboratory 3 rd IPWG 2006: 6 RVL 2/14/2016 CRYSTAL-FACE July

MIT Lincoln Laboratory 3 rd IPWG 2006: 7 RVL 2/14/2016 Mesoscale and Cloud Models Why use mesoscale models? –Explicit forecasts of cloud and precipitation hydrometeors Clouds Convective storms –Detailed initial condition specification Terrain Land-use Meteorological observations Approach –Detailed storm simulations –Validate with surface radar observations –Apply satellite radiative transfer algorithms

MIT Lincoln Laboratory 3 rd IPWG 2006: 8 RVL 2/14/2016 Mesoscale Model v5 (MM5) Parameterizations 1 km horizontal resolution 32 vertical levels (surface to 100 mb) 15 minute resolution output Lower/lateral boundary conditions from Rapid Update Cycle (RUC-20 km) Explicit microphysics (Reisner2 - six phases) Boundary layer physics (MRF) Radiation scheme (IR SW+LW cloud interactions) Cold starts (~ 2-5 hours before target time)

MIT Lincoln Laboratory 3 rd IPWG 2006: 9 RVL 2/14/2016 Radiative Transfer Models Atmospheric absorption and scattering: TBSCAT –P. Rosenkranz, “Radiative Transfer Solution using Initial Values in a Scattering and Absorbing Atmosphere with Reflective Surface,” IEEE Transactions on Geoscience and Remote Sensing, 40(8): , Aug Surface emissivity: –Water - fastem S. English & T. Hewison, “A fast generic millimetre-wave emissivity model,” In Proceedings of SPIE, Vol. 3503, 1998 –Land - Used randomly chosen values based on measurements from: F. Weng, et al., “A microwave land emissivity model,” J. of Geophysical Research, Vol. 106, No. D17, Sept. 2001

MIT Lincoln Laboratory 3 rd IPWG 2006: 10 RVL 2/14/2016 Radiative Transfer / NWP Interface Issues Each level requires hydrometeor density per drop radius MM5 US Standard 1976 Pressure [mb] Mass Density [g/m 3 ] Radius [mm] Mass Density [g/m 3 ] graupel snow rain 100 mb Sekhon-Srivastava Marshall-Palmer

MIT Lincoln Laboratory 3 rd IPWG 2006: 11 RVL 2/14/2016 Histograms of MM5-simulated and AMSU-observed brightness temperatures for twenty-four storms at 15-km resolution (~3000 km square) AMSU-B channel 5 (183.31±7 GHz) AMSU-A channel 5 (53.60 GHz) Histograms of Simulated and Observed Brightness Temperatures (MIT RLE) Surussavadee & Staelin July 2005 AMSU = Advanced Microwave Sounding Unit (space-based)

MIT Lincoln Laboratory 3 rd IPWG 2006: 12 RVL 2/14/2016 Surussavadee & Staelin July 2005 Electromagnetic Modeling of Precipitation Example: Frequency Dependence of Particle Type Rosette Plate Column Ice habits studied (DDSCAT) Sphere Fitting for snow F( ) Fitting for graupel F( ) F( ) is “ice factor” (normalized density)

MIT Lincoln Laboratory 3 rd IPWG 2006: 13 RVL 2/14/2016 Reflectivity Comparison for 11Jul02 Composite radar reflectivity over a GOES visible image Simulated reflectivity using MM5 output

MIT Lincoln Laboratory 3 rd IPWG 2006: 14 RVL 2/14/ GHz T B Image Comparison Histograms of the images above are on the next slide Brightness Temperature [Kelvin] Simulated (MM5)Actual (NAST-M)

MIT Lincoln Laboratory 3 rd IPWG 2006: 15 RVL 2/14/ GHz Histogram Comparison Brightness Temperature [Kelvin] Simulated Data (MM5) Actual Data (NAST-M) Simulations (Precipitation only)

MIT Lincoln Laboratory 3 rd IPWG 2006: 16 RVL 2/14/ /- 3.5-GHz T B Image Comparison Histograms of the images above are on the next slide Brightness Temperature [Kelvin] Simulated (MM5)Actual (NAST-M)

MIT Lincoln Laboratory 3 rd IPWG 2006: 17 RVL 2/14/ /- 3.5-GHz Histogram Comparison Brightness Temperature [Kelvin] Simulated Data (MM5) Actual Data (NAST-M) Simulations (Precipitation only)

MIT Lincoln Laboratory 3 rd IPWG 2006: 18 RVL 2/14/ /- 10-GHz T B Image Comparison Histograms of the images above are on the next slide Brightness Temperature [Kelvin] Simulated (MM5)Actual (NAST-M)

MIT Lincoln Laboratory 3 rd IPWG 2006: 19 RVL 2/14/ /- 10-GHz Histogram Comparison Brightness Temperature [Kelvin] Simulated Data (MM5) Actual Data (NAST-M) Simulations (Precipitation only)

MIT Lincoln Laboratory 3 rd IPWG 2006: 20 RVL 2/14/ / GHz T B Image Comparison Histograms of the images above are on the next slide Brightness Temperature [Kelvin] Simulated (MM5)Actual (NAST-M)

MIT Lincoln Laboratory 3 rd IPWG 2006: 21 RVL 2/14/ / GHz Histogram Comparison Brightness Temperature [Kelvin] Simulated Data (MM5) Actual Data (NAST-M) Simulations w/ precipitation

MIT Lincoln Laboratory 3 rd IPWG 2006: 22 RVL 2/14/2016 Final Thoughts Numerical atmospheric and radiative transfer modeling capabilities are rapidly expanding. Resources needed to further improve and validate these models are becoming available on a wide scale: –Computational capacity –Global, high-resolution microwave and millimeter-wave observations New statistical characterizations of model performance can be used to “calibrate” model-generated ground-truth data for retrieval simulations, etc. Towards all-weather radiance assimilation: –Improved reconciliation of modeled and measured radiances is vital –Study of spectral/spatial/temporal system requirements

3 rd IPWG 2006: 23 RVL 2/14/2016 MIT Lincoln Laboratory Backup Slides

MIT Lincoln Laboratory 3 rd IPWG 2006: 24 RVL 2/14/2016 Simulations from 11Jul02 Brightness Temperature [Kelvin] Simulated (MM5)Actual (NAST-M) 50.3-GHz ( ) 118-GHz ( /- 3.5)

MIT Lincoln Laboratory 3 rd IPWG 2006: 25 RVL 2/14/2016 Simulations from 11Jul02 Brightness Temperature [Kelvin] Simulated (MM5)Actual (NAST-M) 183-GHz ( /- 10) 425-GHz ( /- 2.15)