Patterns in the CERES Global Mean Data, Part 3. Cloud Area Fraction, Atmospheric Energy Budgets, DLR Update. Miklos Zagoni

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1 Patterns in the CERES Global Mean Data, Part 3. Cloud Area Fraction, Atmospheric Energy Budgets, DLR Update β eff eff = β obs ε obs ε IR IR Miklos Zagoni miklos.zagoni@t-online.hu 2018 Earth Radiation Budget Workshop / 30 th CERES Science Team Meeting September 10-13, 2018, NCAR, Boulder, CO. Instead of the traditional paradigm of properties define processes, study how processes define property (Graeme Stephens, GEWEX Closing Plenary, May 11, 2018)

2 Flashback Observing and Modeling Earth s Energy Flows Surveys in Geophysics (2012) Special Issue Flux name (all-sky) Source Value W/m 2 SFC LW Up Kato et al. 398 ± 3 SFC LW Dn Kato et al. 345 ± 7 SFC Net Kato et al. 106 ± 12 TOA LW Up Solar Abs by Atm Solar Abs by SFC LW CRE Trenberth and Fasullo Trenberth and Fasullo Trenberth and Fasullo Stevens and Schwartz

3 Flashback Observing and Modeling Earth s Energy Flows Surveys in Geophysics (2012) Special Issue Flux name (all-sky) Source Value W/m 2 N N UNIT W/m 2 Diff W/m 2 SFC LW Up Kato et al. 398 ± SFC LW Dn Kato et al. 345 ± SFC Net Kato et al. 106 ± TOA LW Up Solar Abs by Atm Solar Abs by SFC LW CRE Trenberth and Fasullo Trenberth and Fasullo Trenberth and Fasullo Stevens and Schwartz

4 Costa and Shine (2012) J Atmos Sci Global annual means, LBL RT, clear-sky ULW = 386 Wm -2 OLR = 259 Wm -2 ATM = 194 Wm -2 G = 127 Wm -2 WIN = 65 Wm -2 WIN G ATM OLR ULW 2OLR CS12 = Pattern = 65 / 130 / 195 / 260 / 390 / 520 Integer ratios: 1 / 2 / 3 / 4 / 6 / 8 Diff (Wm -2 ) =

5 Costa and Shine (2012) J Atmos Sci Global annual means, LBL RT, clear-sky ULW = 386 Wm -2 OLR = 259 Wm -2 ATM = 194 Wm -2 G = 127 Wm -2 WIN = 65 Wm -2 Clear-sky: 2 OLR = E(SFC) 2 G = OLR 2 WIN = G 2 ATM = ULW WIN G ATM OLR ULW 2OLR CS12 = Pattern = 65 / 130 / 195 / 260 / 390 / 520 Integer ratios: 1 / 2 / 3 / 4 / 6 / 8 Diff (W/m 2 ) =

6 SFC (SW + LW) energy in = 2 TOA LW out Clear-sky TOA SW in TOA SW up TOA LW up SFC SW down SFC SW up SFC SW in(down up) SFC LW down SFC SW + LW absorbed TOALW out 2 TOA LW out Diff 2TOA LW up Diff EBAF Ed Clear-sky, EBAF Ed2.8 Surface energy absorbed SW + LW (Wm -2 ): (SW down SW up) + LW down = ( ) = = TOA LW out = TOA LW out = = Diff = 0.59 Wm =

7 SFC SW + LW energy in = 2OLR(all) + SFC LWCRE All-sky TOA SW in TOA SW up TOA LW up SFC SW down SFC SW up SFC SW in SFC LW down SFC SW + LWabsorbed SFC LW up SFC Net G SFC LWCRE 2TOA LW Up + SFC LWCRE Diff EBAF Ed SFC energy in (SW + LW ) = = = = 2 x TOA LW out + SFC LWCRE = 2 x = Diff = EEI? = 0.59 W m -2

8 EBAF Ed4.0 All-sky TOA SW in TOA SW up TOA LW up SFC SW down SFC SW up SFC SW in SFC LW down SFC SW + LWabsorbed SFC LW up SFC Net G SFC LWCRE 2TOA LW Up + SFC LWCRE Diff Ed All-sky, Ed4.0 Energy absorbed SFC (W m -2 ): SW in + LW in = = x OLR + SFC LWCRE = 2 x = Diff = 2.54 W m -2

9 Stephens et al. (2012) Nat Geosci

10 Stephens et al. (2012) Nat Geosci

11 Wild et al (2013) update 1 = 26.6 W/m 2, max(wild-edmz) = -3.8 W/m 2 (DLR) g

12 Diff = 0.05 W/m2

13 Best fit: 1 = Wm -2, max = 2.7 Wm -2 (Sensible Heat)

14 Kato et al (2018, J Clim) Table 5 Flux name (all-sky) Ed4 (W m -2 ) N (integer) EdMZ (W m -2 ) Ed4 EdMZ (W m -2 ) TOA SW insolation TOA SW up 99.1 TOA LW up SW down SW up SW net LW down LW up LW net SW + LW net AtmSW net AtmLW net AtmSW + LW net

15 Brussels, Atomium

16 CERES EBAF Ed4.0 and EdMZ Fluxes

17 Trenberth and Fasullo (2012) 5.6 % 94.4 % 100 % Earth s atmosphere: almost IR-opaque (94 %)

18 The opacity gap can be closed by the blanketing effect of clouds 5.6 % 94.4 % 100 % Note that the largest effect of clouds on the outgoing longwave flux is in the atmospheric window (8 12 mm). (Kiehl and Trenberth 1997)

19 A Conceptual Approach: Closed Shell Geometry SW-transparent, LW-opaque, non-turbulent

20 Deduction, Step 1. UNIT change 1 => 3 Allow ONE unit of atmospheric SW-absorption: Solar Absorbed Atmosphere (SAA) = 1, Solar Absorbed Surface (SAS) = 2

21 After unit change 3 => 9 allow ONE unit for partial atmospheric LW-transparency WIN = 1 ATM = 8 Incl. clouds

22 introduce ONE unit for cloud LW radiative effect WIN = 1 1 ATM = 8 LW CRE Incl. clouds 1

23 and close the window with it! The result is an effectively IR-opaque system. WIN = 1 LW CRE LW CRE 1 Incl. clouds ATM = 8 From a surface perspective: what is lost in the window is gained back by the greenhouse effect of clouds

24 CLEAR-SKY basics: SFC / TOA = TWO / ONE UNIT(clear) = WIN(clear)= 66.7W/m 2, f(clear) = OLR/ULW = 2/3 ASR ATM(clear) up OLR clear WIN(clear) E(SFC, clear) = SW in + LW in = 2 OLR(clear)

25 ALL-SKY basics: SFC/TOA= 2OLR + 1UNIT(all) UNIT(all) = LWCRE = W/m 2, f(all) = 3/5 ASR ATM up OLR all WIN LWCRE = 1 = E(SFC, all) = SW in + LW in = 2 OLR(all) + 1 UNIT(all)

26 EdMZ EdMZ EdMZ Loeb et al. (2017)

27 Clouds Effective (IR-opaque) Cloud Area Fraction Does a Cloud Area Fraction follow from the geometric pattern? Yes, it does. WIN(clear) = 1/4 OLR(clear) = 1/6 ULW WIN(all) = 1/9 OLR(all) = 1/15 ULW This defines beta as: WIN(all) = (1 β eff ) WIN(clear) => 1/15 = (1 β eff ) 1/6 β eff = 3/5 = 0.6

28 Observed Effective Cloud Area Fraction Effective Cloud Amount = Observed Cloud Amount weighted by Cloud IR Emissivity β eff = β obs ε IR CERES SYN1deg Apr2000-March2018: β obs = (0.665) ε IR = (0.828) β eff = = 0.58 (0.55) 0.6 = 0.68 x 0.88 TRUE beta eff?

29 Stubenrauch et al. BAMS (2013) β eff : AIRS = 0.46; ISCCP = 0.51; HIRS = 0.61; MODIS = 0.66

30 CLOUDY basics: SFC/TOA= 2OLR + 1UNIT(cloudy) UNIT(cloudy) = OLR(clear) OLR(cloudy) = 44.45W/m 2, f(cloudy) = 5/9 Cloudy up OLR cloudy WIN βeff = 3/5 E(SFC, cloudy) = SW in + LW in = 2OLR(cloudy) + 1 UNIT (cloudy)

31 CLOUDY basics: SFC/TOA= 2OLR + 1UNIT(cloudy) UNIT(cloudy) = OLR(clear) OLR(cloudy) = 44.45W/m 2, f(cloudy) = 5/9 ASR Cloudy up OLR cloudy WIN βeff = 3/5 3 C 8 + C E(SFC, cloudy) = SW in + LW in = 2OLR(cloudy) + 1 UNIT (cloudy)

32 OLR(all-sky) = 9 = W/m Cloudy OLR = 4 1 OLR clear = 4 3 = ATM up WIN = 1 βeff = βeff = ULW = = 240 W/m 2, Turb= 53 W/m 2 LWCRE ULW= =160 W/m 2, Turb= =53 Surface ULW = 400 W/m 2 (15), Turbulent fluxes = 107 W/m 2 (4), UNIT = 1 = W/m 2

33 Effective cloud layer at work f(all) = OLR(all)/ULW = 240/400 = 9/15 = 3/5 = β eff f(all) = all-sky transfer function = OLR(all)/ULW = beta(eff) The cloud-covered part of the surface radiates OLR

34 Cloud philosophy forβeff = 3/5 The cloud-covered part of the SFC is βeff = 0.6 the effective clear-sky area fraction is (1 βeff) = 0.4 the Clear/Cloudy area ratio is 0.4 / 0.6 = 2/3. βeff = 3/5 = OLR(all)/ULW = f(all) Clear/Cloudy ratio = 2/3 = OLR(clear)/ULW = f(clear). OLR(clear) OLR(all) = LWCRE defines UNIT(all). OLR(clear) OLR(cloudy) = LWCRE/β defines UNIT(cloudy) (2/3) (3/5) = 1/15 ULW = UNIT(all) (1/15) / (3/5) = 1/9 ULW = UNIT(cloudy) UNIT(cloudy) / (2/3) = 1/6 ULW = UNIT(clear) = WIN(clear)

35 Basic ratios forβ eff = 3/5 Hierarchy of energy units and levels WIN(all) = βeff WIN(cloudy) + (1 βeff) WIN(clear) LWCRE(all) =βeff LWCRE(cloudy) + (1 βeff) LWCRE(clear) WIN(cloudy) = LWCRE(clear) = 0, hence: UNIT(all) = OLR(clear) OLR(all) = LWCRE(all) = W/m 2 UNIT(cloudy) = OLR(clear) OLR(cloudy) = LWCRE(cloudy) = W/m 2 UNIT(clear) = OLR(clear) / 4 = WIN(clear) = W/m 2 ULW = 6 UNITS(clear) = 9 UNITS(cloudy) = 15 UNITS(all) OLR(clear) = 4 UNITS(clear) = 6 UNITS(cloudy) = 10 UNITS(all) G(clear) = 2 UNITS(clear) = 3 UNITS(cloudy) = 5 UNITS(all) G(cloudy) = 4 UNITS(cloudy) G(all) = 6 UNITS(all) E(SFC, clear) = 20 UNITS(all) = 12 UNITS(cloudy)= 8 UNITS(clear) E(SFC, clear) = OLR(clear) + OLR(clear) = 8 UNITS(clear) E(SFC, cloudy) = OLR(cloudy) + OLR(clear) = 11 UNITS(cloudy) E(SFC, all) = OLR(all) + OLR(clear) = 19 UNITS(all) E(ATM, all) = E(SFC, all) + 2 LWCRE(all) = 21 UNITS(all)

36 Cloudy/Clear Conributions, β eff = 3/5 Atm SW Abs: Clear = = 30, Cloudy = = 50 W/m 2 => Atm SW Abs (all) = 80 W/m2, Cloudy / Clear = 5 / 3 Turbulent: Cloudy / Clear = 1 / 1 Cloudy part: = 53.4 W/m 2 Clear-sky part: = 53.4 W/m 2 All-sky mean turbulence = W/m 2 Greenhouse: Cloudy / Clear = 2 / 1 Cloudy part: = W/m 2 Clear-sky part: = 53.4 W/m 2 All-sky mean G(all) = W/m 2 OLR: Cloudy (222.3) 0.6 = W/m 2 = G(clear) = 5 Clear (266.8) 0.4 = W/m 2 = Turb = 4 Perrfect. (TOO perfect, Monsieur Poirot would say.)

37 Clear-sky area division: 5/6, 1/6 Within the clear-sky part of the atmosphere, there is also an opaque region (5/6 of the surface) and a transparent one (1/6). 6/ = = OLR(all) = = ULW 5/6 1/6 5/6 E(SFC, clear) = W/m 2 = 2 OLR(cloudy) 1/6 E(SFC, clear) = 88.9 W/m 2 = 2 UNITS(cloudy) E(SFC, clear) = 2 OLR(cloudy) + 2 LWCRE(cloudy) The opaque area(5/6) contributes to OLR(clear) by (OLR(clear) WIN) = ULW/2 = 5/6 OLR(all)=200.1 W/m 2, The transparent area(1/6) = Turb/2 = 1/6 ULW= 66.7 W/m 2. The opaquepart ofthe cloudless atmosphere extends the cloudy opacity by(5/6 2/5) = 1/3,toan all-skyof 3/5 + 1/3 = 14/15. The nominal(per unit area) radiations at the clear-sky opaque and transparent regions are OLR(all) and ULW. The OLR(clear) OLR(all) difference (=LWCRE) is the clear-sky area-weighted WIN(clear) = 2/5 WIN(clear) = WIN(all) Though this be madness, yet there is method in t.

38 Opaque area contributions: 3/5, 1/3 Opacity = 14/15 = 3/5 by clouds + 2/5 5/6 = 1/3 by GHGs Same area-weighted differences (2): = = 53.4 W/m 2 OLR: 3/5 5/9 ULW = 133.4; 1/3 3/5 ULW = 80.0; 1/15 ULW = Cloud-opaqe area: 3/5 GHG-opaque area: 1/3 Transp.1/15 60% 33.3% 6.7% 3/ /5 5/ /5 1/ (5) 80.0 (3) 26.68(1) OLR = GHG-opaque nominal rad. The surplus in the window region is leveled back by the minus over clouds. GHG-opaque / cloud-opaque contribution ratio: 80.0 / = 3/5

39 The OLR(clear) surplus over the opaque-cloudy is the area-weighted surplus of OLR(clear) to opaque-clear. OLR(clear) OLR(cloudy) = LWCRE / βeff = W/m 2 OLR(clear) ATM(clear) = WIN(clear) = 66.7 W/m 2 => LWCRE / (3/5) = 2/3 WIN(clear) => WIN(clear) 2/5 = WIN(all) = LWCRE. Cloudy-opaque + clear-sky GHG-opaque OLR(clear) OLR(all) = LWCRE = WIN(all) OLR(cloudy) = /3 LWCRE OLR(all) = LWCRE 5/6 2/ = Transparent OLR(transp) = ULW = /6 2/5 ULW = WIN = / = OLR(all) OLR(cloudy) = 2/3 LWCRE OLR(clear) OLR(cloudy) = 5/3 LWCRE OLR(clear) ATM(clear) = WIN(clear)

40 g

41 Earth s atmosphere is effectively IR-closed

42 Downward Longwave Update Mean Diff 13OLR/9 DLR(all-sky) OLR(all-sky) Year

43 DLR 13/9 OLR(all) EBAF Ed4.0 running 12-months means April 2000-March 2018 Range [-3.0; -0.5], Bias 1.8 W m -2, Trend +0.3 W m -2 / decade OLR(all) = W/m 2 => TRUE DLR = 13/9 OLR(all)= 346.9W/m 2

44 Wild et al AIP EdMZDLR = (13/9) OLR(all) EdMZprojection 21 st century: SFC LW Dn= OLR 13/9 = 13UNITS= ±3 Wm -2 SFC LW Up= OLR 15/9 = 15UNITS= ±3 Wm -2