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)
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 238.5 78 161 26.5
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 ± 3 15 397.5 0.5 SFC LW Dn Kato et al. 345 ± 7 13 344.5 0.5 SFC Net Kato et al. 106 ± 12 4 106.0 0.0 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 238.5 9 238.5 0.0 78 3 79.5-1.5 161 6 159.0 2.0 26.5 1 26.5 0.0
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 = 65 127 194 259 386 518 Pattern = 65 / 130 / 195 / 260 / 390 / 520 Integer ratios: 1 / 2 / 3 / 4 / 6 / 8 Diff (Wm -2 ) = 0 3 1 1 4 2
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 = 65 127 194 259 386 518 Pattern = 65 / 130 / 195 / 260 / 390 / 520 Integer ratios: 1 / 2 / 3 / 4 / 6 / 8 Diff (W/m 2 ) = 0 3 1 1 4 2
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 Ed2.8 339.87 52.50 265.59 244.06 29.74 214.32 316.27 530.59 265.59 531.18 0.59 531.18 0.59 Clear-sky, EBAF Ed2.8 Surface energy absorbed SW + LW (Wm -2 ): (SW down SW up) + LW down = (244.06 29.74) + 316.27 = 214.32 + 316.27 = 530.59 TOA LW out = 265.59 2 TOA LW out = = 531.18 Diff = 0.59 Wm -2 214.32 + 316.27 = 2 265.59 0.59
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 Ed2.8 339.87 99.62 239.60 186.47 24.13 162.34 345.15 507.49 398.27 109.22 158.67 28.88 508.08 0.59 SFC energy in (SW + LW ) = = 162.34 + 345.15 = 507.49 = 2 x TOA LW out + SFC LWCRE = 2 x 239.6 + 28.88 = 508.08 Diff = EEI? = 0.59 W m -2
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 Ed4.0 340.04 99.23 240.14 187.04 23.37 163.67 344.97 508.64 398.34 110.30 158.20 30.90 511.18 2.54 All-sky, Ed4.0 Energy absorbed SFC (W m -2 ): SW in + LW in = 163.67 + 344.97 = 508.64 2 x OLR + SFC LWCRE = 2 x 240.14 + 30.90 = 511.18 Diff = 2.54 W m -2
Stephens et al. (2012) Nat Geosci
Stephens et al. (2012) Nat Geosci
Wild et al (2013) update 1 = 26.6 W/m 2, max(wild-edmz) = -3.8 W/m 2 (DLR) g
Diff = 0.05 W/m2
Best fit: 1 = 26.68 Wm -2, max = 2.7 Wm -2 (Sensible Heat)
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 340.0 TOA SW up 99.1 TOA LW up 240.0 9 240.0 0.0 SW down 187.1 7 186.7 0.4 SW up 23.3 1 26.67-3.4 SW net 163.8 6 160.0 3.8 LW down 344.7 13 346.7-2.0 LW up 398.3 15 400.0-1.7 LW net -53.6 2-53.3-0.3 SW + LW net 110.2 4 106.7 3.5 AtmSW net 77.1 3 80.0-2.9 AtmLW net -186.5 7-186.7 0.2 AtmSW + LW net -109.4 4-106.7-2.7
Brussels, Atomium
CERES EBAF Ed4.0 and EdMZ Fluxes
Trenberth and Fasullo (2012) 5.6 % 94.4 % 100 % Earth s atmosphere: almost IR-opaque (94 %)
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)
A Conceptual Approach: Closed Shell Geometry SW-transparent, LW-opaque, non-turbulent
Deduction, Step 1. UNIT change 1 => 3 Allow ONE unit of atmospheric SW-absorption: Solar Absorbed Atmosphere (SAA) = 1, Solar Absorbed Surface (SAS) = 2
After unit change 3 => 9 allow ONE unit for partial atmospheric LW-transparency WIN = 1 ATM = 8 Incl. clouds
introduce ONE unit for cloud LW radiative effect WIN = 1 1 ATM = 8 LW CRE Incl. clouds 1
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
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) 286.7 20.0 73.3 E(SFC, clear) = SW in + LW in = 2 OLR(clear)
ALL-SKY basics: SFC/TOA= 2OLR + 1UNIT(all) UNIT(all) = LWCRE = 26.68 W/m 2, f(all) = 3/5 ASR ATM up OLR all WIN LWCRE = 1 = 26.68 240.4 80.1 3 E(SFC, all) = SW in + LW in = 2 OLR(all) + 1 UNIT(all)
EdMZ EdMZ EdMZ 99.60 53.36 46.24 240.12 266.8 26.68 0.33 19.89 19.56 Loeb et al. (2017)
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
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 = 0.675 (0.665) ε IR = 0.863 (0.828) β eff = 0.675 0.863 = 0.58 (0.55) 0.6 = 0.68 x 0.88 TRUE beta eff?
Stubenrauch et al. BAMS (2013) β eff : AIRS = 0.46; ISCCP = 0.51; HIRS = 0.61; MODIS = 0.66
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)
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 208.9 βeff = 3/5 3 C 8 + C 13.3 84.5 E(SFC, cloudy) = SW in + LW in = 2OLR(cloudy) + 1 UNIT (cloudy)
OLR(all-sky) = 9 = 240.12 W/m 2 5 4 Cloudy OLR = 4 1 OLR clear = 4 3 = ATM up WIN = 1 βeff = 0.6 1 βeff = 0.4 10 8 9 2 1 6 2 ULW = 400 0.6 = 240 W/m 2, Turb= 53 W/m 2 LWCRE ULW=400 0.4=160 W/m 2, Turb=133 0.4=53 Surface ULW = 400 W/m 2 (15), Turbulent fluxes = 107 W/m 2 (4), UNIT = 1 = 26.68 W/m 2
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
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)
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) = 26.68 W/m 2 UNIT(cloudy) = OLR(clear) OLR(cloudy) = LWCRE(cloudy) = 44.47 W/m 2 UNIT(clear) = OLR(clear) / 4 = WIN(clear) = 66.70 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)
Cloudy/Clear Conributions, β eff = 3/5 Atm SW Abs: Clear = 75 0.4 = 30, Cloudy = 84 0.6 = 50 W/m 2 => Atm SW Abs (all) = 80 W/m2, Cloudy / Clear = 5 / 3 Turbulent: Cloudy / Clear = 1 / 1 Cloudy part: 88.9 0.6 = 53.4 W/m 2 Clear-sky part: 133.4 0.4 = 53.4 W/m 2 All-sky mean turbulence = 106.8 W/m 2 Greenhouse: Cloudy / Clear = 2 / 1 Cloudy part: 177.9 0.6 = 106.8 W/m 2 Clear-sky part: 133.4 0.4 = 53.4 W/m 2 All-sky mean G(all) = 160.2 W/m 2 OLR: Cloudy (222.3) 0.6 = 133.4 W/m 2 = G(clear) = 5 Clear (266.8) 0.4 = 106.8 W/m 2 = Turb = 4 Perrfect. (TOO perfect, Monsieur Poirot would say.)
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). 6/5 200.1 = 240.12 = OLR(all) 6 66.7 = 400.2 = ULW 5/6 1/6 5/6 E(SFC, clear) = 444.7 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.
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): 133.4 80.0 = 80.0 26.68 = 53.4 W/m 2 OLR: 3/5 5/9 ULW = 133.4; 1/3 3/5 ULW = 80.0; 1/15 ULW = 26.68 Cloud-opaqe area: 3/5 GHG-opaque area: 1/3 Transp.1/15 60% 33.3% 6.7% 3/5 222.3 2/5 5/6 240.12 2/5 1/6 400.2 133.4 (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 / 133.4 = 3/5
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 = 44.45 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) = 222.3 2/3 LWCRE OLR(all) = 240.12 LWCRE 5/6 2/5 240.12 = 80.0 +2 Transparent OLR(transp) = ULW = 400.2 1/6 2/5 ULW = WIN = 26.68 3/5 222.3 =133.4-2 OLR(all) OLR(cloudy) = 2/3 LWCRE OLR(clear) OLR(cloudy) = 5/3 LWCRE OLR(clear) ATM(clear) = WIN(clear)
g
Earth s atmosphere is effectively IR-closed
Downward Longwave Update -1.34 347.25 345.91 240.41 2017-1.80 346.92 345.12 240.18 Mean -1.16 347.49 346.33 240.57 2016-0.44 347.60 347.16 240.65 2015-1.39 347.05 345.66 240.27 2014-1.75 346.92 345.17 240.18 2013-1.83 346.69 344.86 240.02 2012-2.74 346.51 343.78 239.89 3011-2.28 346.96 344.68 240.20 2010-2.24 347.02 344.78 240.25 2009-2.51 346.21 343.70 239.68 2008-2.98 346.90 343.92 240.16 2007-2.06 347.18 345.12 240.36 2006-1.09 346.82 345.73 240.11 2005-1.48 346.85 345.37 240.13 2004-1.71 347.11 345.40 240.31 2003-2.34 347.39 345.06 240.50 2002-1.26 346.65 345.39 239.99 2001-1.97 346.02 344.05 239.55 2000 Diff 13OLR/9 DLR(all-sky) OLR(all-sky) Year
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) = 240.18 W/m 2 => TRUE DLR = 13/9 OLR(all)= 346.9W/m 2
Wild et al. 2017 AIP EdMZDLR = (13/9) OLR(all) EdMZprojection 21 st century: SFC LW Dn= OLR 13/9 = 13UNITS= 346.9 ±3 Wm -2 SFC LW Up= OLR 15/9 = 15UNITS= 400.3 ±3 Wm -2