[89] | 1 | ;+ |
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[164] | 2 | ; ================ |
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| 3 | ; lwdown_clark.pro |
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| 4 | ; ================ |
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[89] | 5 | ; |
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[164] | 6 | ; .. function:: lwdown_clark(sst, qair, cld, tair, ps) |
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| 7 | ; |
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[204] | 8 | ; DESCRIPTION |
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[164] | 9 | ; =========== |
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| 10 | ; |
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[89] | 11 | ; Net longwave from the Clark et al. (1974) bulk formula |
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[164] | 12 | ; Clark, N. E., L. Eber, R. M. Laurs, J. A. Renner, and J. F. T. Saur, |
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| 13 | ; 1974: Heat exchange between ocean and atmosphere in the |
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| 14 | ; eastern North Pacific for 1961-71. NOAA Tech. Rep. NMRS |
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| 15 | ; SSRF-682, National Oceanic and Atmospheric Administration, |
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| 16 | ; U.S. Department of Commerce, Washington, DC, 108 pp. |
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[89] | 17 | ; |
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[164] | 18 | ; See also Gill, p34. |
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| 19 | ; |
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[89] | 20 | ; INPUTS |
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| 21 | ; sst : Sea surface temperature (degC) |
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| 22 | ; qair: specific humidity (g/kg) |
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| 23 | ; cld : cloud cover |
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| 24 | ; tair: surface air temperature (degC) |
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| 25 | ; ps : surface pressure (mb) |
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| 26 | ; OUTPUT |
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| 27 | ; lw : estimated longwave (W/m2) |
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| 28 | ; |
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[164] | 29 | ; EVOLUTIONS |
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| 30 | ; ========== |
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| 31 | ; |
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| 32 | ; $Id$ |
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| 33 | ; |
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| 34 | ; $URL$ |
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| 35 | ; |
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| 36 | ; - fplod 20120319 |
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| 37 | ; |
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| 38 | ; * minimal header |
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| 39 | ; |
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| 40 | ;- |
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| 41 | function lwdown_clark, sst,qair,cld,tair,ps |
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| 42 | ; |
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[89] | 43 | @common |
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[97] | 44 | ; |
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[203] | 45 | eps=.97 ; emissivity of sea-water |
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| 46 | sig=5.67e-8 ; Stefan-Boltzman constant (W/m2/K4) |
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| 47 | Ts=(sst+273.15) ; SST in K |
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| 48 | Ta=(tair+273.15) ; Tair in K |
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[89] | 49 | q=qair/1000. ; specific humidity (kg/kg) |
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[203] | 50 | r=q/(1-q) ; Mixing ratio |
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[89] | 51 | ea=ps*r/(r+.62197) ; Specific humidity into vapor pressure |
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[97] | 52 | ; |
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[89] | 53 | lw= eps*sig*Ts^4*(.39-.05*ea^.5)*(1.-.51*cld^2) $ |
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[97] | 54 | +4.*eps*sig*Ts^3*(Ts-Ta) |
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| 55 | ; |
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[89] | 56 | lwup=eps*sig*Ts^4 |
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[97] | 57 | ; |
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[89] | 58 | lwdown=lwup-lw |
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[97] | 59 | ; |
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[89] | 60 | return, lwdown |
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[97] | 61 | ; |
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[89] | 62 | end |
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