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Routine pmix in Modularized Flux Testbed

Input Parameters:

Lists input parameters and tables explaining options.
ParameterTypeDescription UnitsArgument Number
dyn_in_prmintDynamic input parameter index none1
dyn_in_valfloatDynamic input value. Usually the mean wind speed at the height (zref) of the anemometer. Other input options are friction velocity (magnitude), wind stress (magnitude), and equivalent neutral wind speed (scatterometer wind speed). Altnernatively, this value can be a vector component of the wind (or other such inputs). It should be a vector component in the direction of wave propagation. In a future release, I plan on allowing this to be the u-compoent,. see below2
dyn_in_val2floatDynamic input value 2. This value is usually zero because magnitude of the wind is often entered in dyn_in_val. If a vector component is entered in dyn_in_val, then dyn_in_val is the other vector component. see below2
CONVECTfloatConvective parameter. Recommended value between 0.7 and 1.25. For details see TOGA NOTES #4 none4
CONV_CRITfloatConvergence criterion fraction5
pressurefloatAtmospheric surface pressure. Note that the 2nd most common error in data entry is to enter this value with the wrong units; don't use mb or hPa. Pa6
air_moist_prmintAtmospheric moisture parameter index none7
air_moist_valfloatValue of the parameter corresponding to the above index see below8
sfc_moist_prmintSurface moisture parameter index none9
sfc_moist_valfloatValue of the parameter corresponding to the above index see below10
salinityfloatSalinity. Enter as a fraction (e.g., 0.0349) rather than parts per thousand none11
ss_prmintSeastate parameter index none12
ss_valfloatValue of the parameter corresponding to the above index see below13
t_airfloatAir temperature at the reference height of the thermometer and humidity sensor C14
t_skinfloatSkin temperature of the water. C15
ref_ht_windfloatHeight of the wind observations m16
ref_ht_tqfloatHeight of the temperature observations. Note: in the current version of the code this must equal to height of the humidity observations. m17
astabintAtmospheric stability option none18
flux_modelintWarning level: 0 warnings, 1 no warnings. none19
z0_mom_prmintMomentum roughness length parameterization. To use this input, flux_model must have a value less than zero. none20
z0_TQ_prmintPotential temperature and moisture roughness length parameterization. To use this input, flux_model must have a value less than zero. none21
stable_prmintStability parameterization. If astab=0 (neutral stability) then this setting has no influence. Furthermore, flux_model must have a value less than zero. none22

Options for dynamic input:

Typically wind speed is used as an input to boundary-layer models. However, scatterometers are now producing 'observations' of friction velocity and equivelent neutral wind speed.

dyn_inDescription Units
0Wind speed, relative to the surface current m/s
1Friction velocity (magnitude) m/s
2Surface wind stress (magnitude) N/m^2
3Equivalent neutral wind speed (relative to the surface current) m/s

Options for atmospheric stability condition:

The atmospheric stability in the boundary-layer can be assumed to neutral, or it can be calculated input parameters.

astabDescription Units
0Atmospheric stability is assumed to be neutral none
1Stability is calculated none

Options for seastate parameterizations:

There are six possible seastate assumptions: any one of the following can be treated as known: wind-wave stability parameter (set to 1.0 for local equilibrium), phase speed, wave age, significant wave height, significant slope, and the period of the dominant waves. Caution: in many cases, these wave characteristics will correspond to swell rather than the phase speed of locally wind induced waves.

ss_prmParameter treated as known (ss_val) Units
0Wind-wave stability parameter none
1Phase speed of the dominant waves. Note: in many cases, this phase speed will correspond to the swell rather than the phase speed of locally wind induced waves. Use of the wrong phase speed can lead to large overestimations of fluxes. m/s
2Wave age the dominant waves (cp/u*) none
3Significant wave height (Hs) m
4Significant slope (Hs/l) none
5Period of the dominant waves (Tp) s

Options for atmospheric moisture input:

Choose the moisture parameter that is easiest for you to deal with:

air_moist_prmParameter for moisture of air (air_moist_val) Units
0Specific humidity at the reference height of the thermometer and humidity sensor g vapor / g air
1Relative humidity fraction
2Dew point temperature C
3Wet bulb temperature C

Options for surface moisture input:

Choose the moisture parameter that is easiest for you to deal with:

sfc_moist_prmParameter for moisture of air (sfc_moist_val) Units
0Specific humidity 'at' (near) the surface g vapor / g air
1Relative humidity fraction
2Dew point temperature C
3Wet bulb temperature C

Options for selecting parameterizations to match published flux models:

flux_modelParameter for moisture of air (sfc_moist_val)
0The flux_model variable is not used. Instead, the parameterizations are selected using three variables: z0_mom_prm, z0_TQ_prm, and stable_prm.
1Bourassa, Vincent and Wood (1999, JAS)
2Smith (1988, JGR) version based on a momentum roughness length being a sum of roughesses for a smooth surface and gravity waves (Charnock's constant = 0.011.
3BVW (1999) with Smith (1988) stability parameterization.
4BVW (1999) without roughness from capillary waves.
5BVW (1999) without surface tension in phase speed parameterizaiton.
6BVW (1999) without roughness from capillary waves, and without surface tension in phase speed parameterizaiton.
7Taylor and Yelland (2001, JTECH) parameterization.
8Taylor and Yelland (2001, JTECH) parameterization with additional momentum roughness length due to capillary waves.
9Bourassa (2006) roughness length parameterization and CFC (Clayson, Fairall, and Curry) roughness length parameterization for potential temperature and moisture.
10Bourassa (2006) roughness length parameterization and CFC (Clayson, Fairall, and Curry) roughness length parameterization for potential temperature and moisture, and a displacement height of 80% of the significant wave height. This assumption about displacement height works for wind driven waves; however, a displacement height of zero is a better assumption for swell.
11Bourassa (2006) roughness length parameterization and Zilitinkevich et al. roughness length parameterization for potential temperature and moisture.
12Bourassa (2006) roughness length parameterization and LKB (Liu, Katsaros, and Businger; 1979; JAS) roughness length parameterization for potential temperature and moisture.
13Bourassa (2006) roughness length parameterization and COARE3.0 (ref) roughness length parameterization for potential temperature and moisture.
14Bourassa (2006) roughness length parameterization and wall theory roughness length parameterization for potential temperature and moisture.
15Bourassa (2006) roughness length parameterization and CFC (Clayson, Fairall, and Curry) roughness length parameterization for potential temperature and moisture. The surface is also considered to be covered with oil modeled after the DWH spill.

Roughness Length Options for Momentum:

This option is applied only if flux_model < 0.

z0_mom_prmParameterizaton for Momentum Roughness Length (z0_mom_prm)
0Bourassa, Vincent and Wood (1999, JAS) momentum roughness length parameterization.
1 Bourassa (2006) momentum roughness length parameterization.
2Taylor and Yelland (1999, JTECH) momentum roughness length parameterization.
3 Bourassa (2006) momentum roughness length parameterization modified for an oil slick modeled after the DWH slick.

Roughness Length Options for Potential Temperature and Moisture:

This option is applied only if flux_model < 0. Note that the potential temperature and moisture roughness lengths are calculated separately; however, the type of parameterization comes from the same source.

z0_mom_prmParameterizaton Type for Potential Temperature and Moisture Roughness Length (z0_mom_prm)
0CFC (Clayson, Fairall and Curry; 1996, JGR) parameterization.
1 Zilitinkevich et al. (2001) roughness length parameterization.
2LKB (Liu, Katsaros, and Businger; 1979, JAS) parameterization.

Boundary-Layer Stability Options:

This option is applied only if flux_model < 0.

stable_prmParameterizaton Type for Boundary-Layer Stability (stable_prm)
0BVW (Bourassa, Vincent and Wood; 1999; JAS) collection of parameterizations.
1 Smith (1988; JGR) collection of parameterizations.


Model Output:

Vector components are calculated parallel and perpendicular to the direction in which the dominant waves are propagating. The first component is parallel the direction of wave propagation, and the second component is perpendicular to the first (while looking down it is 90 counter-clockwise from the first component; i.e., in a right handed coordinate system with the positive vertical axis pointing upward). For most applications there will be insufficient wave information, requiring the assumption of local wind-wave equilibrium. This assumption implies that the wind and the waves are moving in the same direction; which results in the first component of the vectors being parallel to the wind direction, and the second component being zero.

All output is single precision floating point.

The routine returns a integer value (i.e., a warning flag). Positive values indicate a lack of specific problems. If there are problems with missing input, non-convergence within the algorithm, or if the modeled physics obviously fails to apply, then the output is set to -1. For example, if the thickness of the boundary layer is too small (i.e., the absolute value of the Obhukov scale length less than or equal to 1 m) then the warning flag is set at -1.

ParameterTypeDescription UnitsArgument Number
shffloatsensible heat flux W m-223
lhffloatlatent heat fluxW m-224
tauvector floatstress vector. There are more details on the conversion to zonal and meridional components. N m-225
u_starvector floatfriction velocity (u*) m s-126
t_starfloatscaling term for potential temperature (T*) C27
q_starfloatscaling parameter for moisture (q*) none28
z_over_Lfloatdimensionless Monin-Obhukov scale length none29
wave_agefloatwave age, cp/u* none30
dom_phs_spdfloatphase speed of dominant gravity waves m s-131
h_sigfloatsignificant wave height m32
ww_stabfloatwind-wave evolution parameter none33
zo_mvector floatmomentum roughness length m34

Last update: Sept. 20, 2012


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