ECPC Contributions to the Coordinated Enhanced Observing Period (CEOP)

1. ECPC Contributions to the Coordinated Enhanced Observing Period (CEOP) Alex Ruane John Roads Masao Kanamitsu ECPC/Scripps

2. Outline CEOP Overview - Participants - ECPC contributions Spinup Characteristics Diurnal Cycles - Methodology - Comparison of diurnal precipitation to TRMM results - Other diurnal cycles’ relation to precipitation cycle

3. CEOP Opportunity Source: CEOP Implementation Plan - Take advantage of ongoing continental-scale experiments and new Earth-observing satellites to examine our ability to understand and model the water cycle

4. - 41 observation sites located in diverse settings - 42-month observing period, from July 2001 - December 2004 - In-situ, model, and satellite data collected for each station

5. CEOP Participants 41 Observing Stations: equipped with radiation and hydrologic instrumentation 6 Satellite Centers: - NASA EOS - NOAA GOES - NOAA POES - USAF DMSP - NASDA GMS - Meteosat 10 Modeling Centers:contributing global grids as well as Model Output Location Time Series (MOLTS) files - ECPC - NCEP - ECMWF - NASA - JMA - CPTEC - NCMRWF - UKMO - BMRC - Environment Canada

6. ECPC Contributions to CEOP 3 Model Versions: (allowing intercomparisons) - NCEP/DOE Reanalysis-2 (RII) driven by RII initial conditions, - ECPC’s Seasonal Forecast Model (SFM) driven by RII initial conditions - Version of the SFM using the NOAH Land Surface Model driven by its own initial conditions 2 Experiment Types: (allowing internal comparisons) - 6-hr Analysis runs initialized at 00, 06, 12, and 18 GMT with 3-hr resolution - 36-hr Forecast runs initialized at 12 GMT with 3-hr resolution Central Collection of Model Output: - Model Output Location Time Series (MOLTS) files store values and profiles of 108 variables at each CEOP location - Full grid variables as well; over 6 Terabytes of data in total

7. Hydrological Issues in Spinup - In idealized long-term mean, expect diurnal cycle to repeat 1.5 cycles during 36 hours - Spinup error drops off as forecast moves forward - Hydrological Variables particularly affected by initial soil moisture conditions - Need to be careful when running SFM using RII initializations - Motivation for comparing RII/SFM experiment with SFM/SFM experiments 2002 mean of RII 36-hr forecasts over ARM Southern Great Plains Site

8. Diurnal Cycle Examinations - Least-Squares fit of diurnal and bidiurnal harmonics to variable time series. - Result does not accurately regenerate time series, but draws out phase and comparative amplitude information Source: JJA 2002, from RII ft15-36

9. TRMM Observations of the Diurnal Cycle Source: Nakamura, May 2004 GEWEX Newsletter - Tropical Rainfall Measuring Mission (TRMM) shows late afternoon peak over most land areas - Not broadly consistent, definite land-sea contrast - Only covers ±40˚ latitude

10. GSM Diurnal Cycle Reproduction - Land/Sea differences - Argentina early morning max - Guiana Coast afternoon max - Caribbean morning max - Central US evening max - Himalayan morning max - Low amplitude regions - Smaller-scale features can be seen in Africa, India, Indonesia, and China Source: JJA 2002, from RII ft15-36

11. Making Sense Of the Diurnal Precipitation Cycle Model allows global coverage and CEOP period allows for several intervals to be examined. Can we explain the geographical variations?

12. Making Sense Of the Diurnal Precipitation Cycle Approaches using normalized amplitudes and other statistical processes may allow us to examine: - areas with lower mean amplitudes - oceanic cycles - specific regions (No Amplitude Fading)

13. Making Sense Of the Bidiurnal Precipitation Cycle - Inclusion of bidiurnal cycle, seems to constructively interfere at diurnal harmonic’s max - Overall smaller amplitude than diurnal harmonic, but in some places comparable

14. Other Diurnal Cycles - Latent Heat Flux - Radiatively-forced, could explain mid-afternoon maxima. - Seasonal cycle in amplitudes leans toward Summer Hemisphere

15. Other Diurnal Cycles - Vapor Flux Divergence - Dynamically forced by features such as the low level jet. - Vapor Flux Convergence peak is 12 hours later, could explain later precipitation maximum over the Western U.S. and earlier precipitation maximum over Himalayas.

16. Other Diurnal Cycles - Convective Heating Rate - Allows examinations of diurnal convection cycles

17. Other Diurnal Cycles - 2-meter Temperature Mostly as expected - note polar night

18. Other Diurnal Cycles - 2-meter Temperature Subtle coastal structure could merit some further study, probably with coupled version of the RSM.

19. Conclusions - CEOP provides opportunity to validate GSM results and to compare GSM to other major models - GSM performs fairly well in diurnal precipitation cycle comparison with TRMM - Further study of regional diurnal cycle components may help us to better understand the model’s performance