Studies of columnar observations and model outputs. Brian Mapes University of Miami with thanks to many data producers and sharers

Transcription

1 Studies of columnar observations and model outputs Brian Mapes University of Miami with thanks to many data producers and sharers

2 Looking under the hood of monthly mean data points Time sections: f(submonthly time x pressure) a vast, rich domain complementary to typical climate model examination space (lat x lon x months) Natural domain for observations Sensible domain for physical processes

3 Shortcomings Free-running climate model time axis not directly comparable to observations statistical comparisons of course Models have climate-regime offsets in space, biasing comparisons at a fixed geo-location non-mean statistics that is Submonthly variations (dynamics-driven) a poor proxy for climate sensitivity (thermo-driven) tough luck, we do what we can Eulerian viewpoint a perverse view of weather you re free to leave

4 inescapable programming tedium inescapable programming tedium COARE obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 Common data format, variables, names, units, flux sign conventions, etc. standard raw plots standard stat plots

5 Datasets COARE obs KWAJEX obs LBA obs EPIC, JASMINE (more: ARM? etc?) KWAJEX 3D CRM NCAR CAM GFDL AM2 NASA GMAO (more: CAM-SP?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 All obs are from warm-wet tropics so far - what I have & know best Cloud obs rare: satellite TOA rad in ~GCM-grid areas, but cloud profiles at only a few points (cloud radar) the most GCM-comparable cloud dataset Driving the whole exercise -- an AMIP, at the very least weird experiments, not done real carefully so far. Future?

6 COARE obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 What variables? TOA radiation and cloud forcing cloud fraction and condensed water content (p) humidity (p) vertical motion (p) physical tendencies heating and drying (p) rain CLIMATE IMPACT SCALAR structure within tropo- sphere SCALAR LINK TO HYD CYC

7 What plots? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 CRF: LW+, SW-, net ~0 [obs needclear-sky assumptions] rain RH cld frac [ crude f(rh) here ] Q1, CWC (no obs) wind divergence and vertical grid IFA OBS note: net <0 at rainiest times 100 % 0

8 What stats? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE Lag regressions I: scalars vs. reference variable (here, ref = qbudget-derived IFA rain) TOA rad up: net reflected SW reduced OLR KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 Other rain vars: (here, other obs. estimates models, other rain types)

9 What stats? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) regressions vs. IFA rainfall net ocean shading* ~ -20% of latent heat in rain longwave atm heating ~ 15% of latent heating ~6am diurnal rain peak * straight regression incl. nocturnal zeroes - not really right approach ~1 mm/h x 1d ~24 mm rain cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2

10 What stats? II. lag-height regressions of profile fields vs. surface rain COARE obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 44 km radius MCS-resolving ~1/2 day timescale at a point

11 What stats? regressions vs. surface rainfall SYNOPTIC SCALE (IFA) COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 multiscale (incl. several-day timescales) but no cloud profile observations

12 TOA: obs TOA: obs-forced CRM condensate can t blow away What should areal cloud statistics look 4-8 units, vertical like? KWAJEX 3D CRM thanks Marat up to 16, vertical

13 What stats? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM - IFA GFDL AM2 - IFA NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 regressions vs. surface rainfall - AM2 TOA about balanced, long time scales layers upward development time jitters sometimes zigzag layers july - 10 mm/d

14 What stats? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM - IFA GFDL AM2 - IFA NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 TOA closely balanced, long time scale slow upward development zigzag layers AM2 - a different month nov - 11 mm/d

15 What stats? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM - IFA GFDL AM2 NASA GMAO (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 regressions vs. surface rainfall - CAM CRF not well linked to rain events 3-day waves vertical thanks to convective fraction but condensed water not coherent in vertical jan - 7 mm/d

16 What stats? COARE IFA obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM - IFA GFDL AM2 - IFA GMAO 140E/8N July (super-cam soon?) cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 regressions vs. surface rainfall - GMAO a bit stark but about like IFA upward development, zigzag layers 2xKwajCRM ice content freezing level schism

17 rain event met fields - obs <-KWX IFA->

18 rain event met fields - CAM-IFA <-Jan Dec->

19 rain event met fields - 3 models CAM AM2 GMAO

20 But are these brief rain-event fluctuations a Climate Process? hypothesis Divergence profile in tropical rain events linked to profile of divergent winds linked to profile of total winds? ( -> coupling issues climate by any standard)? Let s look

21 Top- stats of div regression sections (lag-height) Bottom- stats of total wind speed (time-height) each curve shows 1 month of data mean IFA AM2 GMAO CAM stdev w/in 6-day lag section All 3 GCMs have unrealistic surface-intensified div fluctuations stdev mean KWAJEX is 3rd line; LBA vs 850 not right GMAOmidlevel swoop but no near- surface enhancement of wind fluctuations CAMjangly wind profiles

22 wind profile results hypothesis too simplistic BUT Systematic windspeed profile differences from observations are clear at low levels!

23 Regressions wrt TOA CRF events? Weird idea: submonthly TOA CRF has ~no feedback to the weather that causes it, so there s less expectation of a repeatable life cycle Proxy for climate sensitivities?? Maybe, if tau << {days, years, decades, etc.}? Anyway, try it (but I have no obs yet) use 24h smoothing to kill diurnal cycle

24 24h-smoothed TOA -CRF as base time series -- CAM 85W 20S CRF<0, big slow changes SWup>0 Whiter w/clouds at 975 not 925

25 Another month at 85W 20S -- CAM faster changes, polymodal pdf? CRF<0 SWup>0 Complicated mixture of events

26 AM2-85W 20S whiteness varies little; regression structure not stable steady -30ish CRF (Q1 data missing) PBL-based clouds rise to ~550mb here!? Minghua s AM2 midlevel cloud (ISCCP)

27 Cross-forced SCMs (CAM <-> AM2) V. advection of SCM fields by prescribed vertical velocity from other GCM H. advection prescribed (non-interactive) Look at LBA (Amazon) just for fun

28 LBA obs (via Minghua s shop), & GCMs LBA obs (warning: clear sky not careful) CAM AM2 (sorry: Q1 missing)

29 LBA obs CAM AM2

30 LBA models AM2 CAM SCAM driven by AM2 omega Cloud style CAMlike

31 LBA models AM2 CAM SCAM2 driven by CAM omega Cloud style AM2 ish

32 Future plans - team efforts? COARE obs KWAJEX obs LBA obs EPIC, JASMINE KWAJEX CRM NCAR CAM GFDL AM2 NASA GMAO (super-cam soon?) Common data format, variables, names, units, sign conventions standard raw plots standard stat plots cross-forced SCMs SCAM2 driven by CAM SCAM driven by AM2 MORE DATA in (p,t) space SCMs! CRMs! EXPERIMENTS! OBS! other people clickable from Bony index plot co-ra.com/~bem more to come