WaterVaporSat Class Reference

#include <ERF_WaterVaporSaturation.H>

Collaboration diagram for WaterVaporSat:

Static Public Member Functions
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real	svp_water (const amrex::Real &t)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real	svp_ice (const amrex::Real &t)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real	svp_trans (const amrex::Real &t)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real	tq_enthalpy (const amrex::Real &t, const amrex::Real &q, const amrex::Real &hltalt)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	no_ip_hltalt (const amrex::Real &t, amrex::Real &hltalt)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	calc_hltalt (const amrex::Real &t, amrex::Real &hltalt, amrex::Real *tterm=nullptr)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	deriv_outputs (const amrex::Real &t, const amrex::Real &p, const amrex::Real &es, const amrex::Real &qs, const amrex::Real &hltalt, const amrex::Real &tterm, amrex::Real &gam, amrex::Real &dqsdt)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	qsat (const amrex::Real &t, const amrex::Real &p, amrex::Real &es, amrex::Real &qs, amrex::Real *gam=nullptr, amrex::Real *dqsdt=nullptr, amrex::Real *enthalpy=nullptr)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	qsat_water (const amrex::Real &t, const amrex::Real &p, amrex::Real &es, amrex::Real &qs, amrex::Real *gam=nullptr, amrex::Real *dqsdt=nullptr, amrex::Real *enthalpy=nullptr)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	qsat_ice (const amrex::Real &t, const amrex::Real &p, amrex::Real &es, amrex::Real &qs, amrex::Real &gam, amrex::Real &dqsdt, amrex::Real &enthalpy)
AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void	findsp (const amrex::Real &q, const amrex::Real &t, const amrex::Real &p, const bool &use_ice, amrex::Real &tsp, amrex::Real &qsp, int &status)

Static Public Attributes
static constexpr amrex::Real	tmin = amrex::Real(127.16)
static constexpr amrex::Real	tmax = amrex::Real(375.16)
static constexpr int	npcf = 5
static constexpr const amrex::Real	pcf [npcf]

Member Function Documentation

calc_hltalt()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::calc_hltalt ( const amrex::Real &  t, amrex::Real &  hltalt, amrex::Real *  tterm = nullptr  )

inlinestatic

                                                         {
        amrex::Real tc, weight;
        no_ip_hltalt(t, hltalt);
        if (t < tmelt) {
            // Weighting of hlat accounts for transition from water to ice.
            tc = t - tmelt;
            if (tc >= -ttrice) {
                weight = -tc/ttrice;
 
                // polynomial expression approximates difference between es
                // over water and es over ice from 0 to -ttrice (C) (max of
                // ttrice is 40): required for accurate estimate of es
                // derivative in transition range from ice to water
 
                if (tterm)
                {
                    for(auto i = npcf-1; i > 0;  --i) *tterm = pcf[i] + tc*(*tterm);
                    *tterm = *tterm/ttrice;
                }
            }
            else {
                weight = amrex:Real(1);
            }
 
            hltalt = hltalt + weight*lat_ice;
        }
    }

Referenced by findsp(), and qsat().

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deriv_outputs()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::deriv_outputs ( const amrex::Real &  t, const amrex::Real &  p, const amrex::Real &  es, const amrex::Real &  qs, const amrex::Real &  hltalt, const amrex::Real &  tterm, amrex::Real &  gam, amrex::Real &  dqsdt  )

inlinestatic

                                                 {
 
        // Local variables
        amrex::Real desdt;        // d(es)/dt
        amrex::Real dqsdt_loc;    // local copy of dqsdt
 
        if (qs == amrex:Real(1)) {
            dqsdt_loc = amrex::Real(0);
        }
        else {
            desdt = hltalt*es/(R_v*t*t) + tterm;
            dqsdt_loc = qs*p*desdt/(es*(p-omeps*es));
        }
 
        dqsdt = dqsdt_loc;
        gam   = dqsdt_loc * (hltalt/Cp_d);
    }

Referenced by qsat(), qsat_ice(), and qsat_water().

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findsp()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::findsp ( const amrex::Real &  q, const amrex::Real &  t, const amrex::Real &  p, const bool &  use_ice, amrex::Real &  tsp, amrex::Real &  qsp, int &  status  )

inlinestatic

                                     {
 
        //
        // local variables
        //
        int iter = 8;    // max number of times to iterate the calculation
 
        amrex::Real es;                   // sat. vapor pressure
        amrex::Real gam;                  // change in sat spec. hum. wrt temperature (times hltalt/cpair)
        amrex::Real dgdt;                 // work variable
        amrex::Real g;                    // work variable
        amrex::Real hltalt;               // lat. heat. of vap.
        amrex::Real qs;                   // spec. hum. of water vapor
 
        // work variables
        amrex::Real t1, q1, dt, dq;
        amrex::Real qvd;
        amrex::Real r1b, c1, c2, c3;
        constexpr amrex::Real dttol = amrex::Real(1.e-4); // the relative temp error tolerance required to quit the iteration
        constexpr amrex::Real dqtol = amrex::Real(1.e-4); // the relative moisture error tolerance required to quit the iteration
        amrex::Real enin, enout;
 
        c3 = amrex::Real(287.04)*(amrex::Real(7.5)*log(amrex::Real(10.)))/Cp_d;
 
        // Saturation specific humidity at this temperature
        if (use_ice) {
            qsat(t, p, es, qs);
        }
        else {
            qsat_water(t, p, es, qs);
        }
 
        // make sure a meaningful calculation is possible
        if (p <= amrex::Real(5.)*es || qs <= amrex::Real(0) || qs >= myhalf || t < tmin || t > tmax) {
            status = 1;
            // Keep initial parameters when conditions aren't suitable
            tsp = t;
            qsp = q;
            enin = amrex:Real(1);
            enout = amrex:Real(1);
            return;
        }
 
        // Prepare to iterate
        status = 2;
 
        // Get initial enthalpy
        if (use_ice)
            calc_hltalt(t,hltalt);
        else
            no_ip_hltalt(t,hltalt);
 
        enin = tq_enthalpy(t, q, hltalt);
 
        // make a guess at the wet bulb temp using a UKMO algorithm (from J. Petch)
        c1 = hltalt*c3;
        c2 = std::pow(t + amrex::Real(36.), 2);
        r1b = c2/(c2 + c1*qs);
        qvd = r1b * (q - qs);
        tsp = t + ((hltalt/Cp_d)*qvd);
 
        // Generate qsp, gam, and enout from tsp.
        if (use_ice)
            qsat(tsp, p, es, qsp, &gam, &enout);
        else
            qsat_water(tsp, p, es, qsp, &gam, &enout);
 
        // iterate on first guess
        for(auto l = 1; l < iter; ++l) {
 
            g = enin - enout;
            dgdt = -Cp_d * (1 + gam);
 
            // New tsp
            t1 = tsp - g/dgdt;
            dt = abs(t1 - tsp)/t1;
            tsp = t1;
 
            // bail out if past end of temperature range
            if ( tsp < tmin ) {
                tsp = tmin;
                // Get latent heat and set qsp to a value
                // that preserves enthalpy.
                if (use_ice)
                    calc_hltalt(tsp,hltalt);
                else
                    no_ip_hltalt(tsp,hltalt);
 
                qsp = (enin - Cp_d*tsp)/hltalt;
                enout = tq_enthalpy(tsp, qsp, hltalt);
                status = 4;
                break;
            }
 
            // Re-generate qsp, gam, and enout from new tsp.
            if (use_ice)
                qsat(tsp, p, es, q1, &gam, &enout);
            else
                qsat_water(tsp, p, es, q1, &gam, &enout);
 
            dq = abs(q1 - qsp)/std::max(q1,amrex::Real(1.e-12));
            qsp = q1;
 
            // if converged at this point, exclude it from more iterations
            if (dt < dttol && dq < dqtol) {
                status = 0;
                break;
            }
        }
        // Test for enthalpy conservation
        if (abs((enin-enout)/(enin+enout)) > amrex::Real(1.e-4)) status = 8;
        return;
    }

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no_ip_hltalt()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::no_ip_hltalt ( const amrex::Real &  t, amrex::Real &  hltalt  )

inlinestatic

                                                 {
        hltalt = lat_vap;
        // Account for change of lat_vap with t above freezing where
        // constant slope is given by -2369 j/(kg c) = cpv - cw
        if (t >= tmelt) hltalt = hltalt - amrex::Real(2369.0)*(t-tmelt);
    }

Referenced by calc_hltalt(), findsp(), and qsat_water().

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qsat()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::qsat ( const amrex::Real &  t, const amrex::Real &  p, amrex::Real &  es, amrex::Real &  qs, amrex::Real *  gam = nullptr, amrex::Real *  dqsdt = nullptr, amrex::Real *  enthalpy = nullptr  )

inlinestatic

                                                     {
        // Local variables
        amrex::Real hltalt;       // Modified latent heat for T derivatives
        amrex::Real tterm = amrex::Real(0);        // Account for d(es)/dT in transition region
 
        es = svp_trans(t); //estblf(t);
 
        qs = SatMethods::wv_sat_svp_to_qsat(es, p);
 
        // Ensures returned es is consistent with limiters on qs.
        es = std::min(es, p);
 
        // Calculate optional arguments.
        // "generalized" analytic expression for t derivative of es
        // accurate to within 1 percent for amrex::Real(173.16) < t < amrex::Real(373.16)
        calc_hltalt(t, hltalt, &tterm);
 
        if (enthalpy)
        {
            *enthalpy = tq_enthalpy(t, qs, hltalt);
        }
 
        if (gam && dqsdt)
        {
            deriv_outputs(t, p, es, qs, hltalt, tterm, *gam, *dqsdt);
        }
    }

Referenced by findsp().

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qsat_ice()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::qsat_ice ( const amrex::Real &  t, const amrex::Real &  p, amrex::Real &  es, amrex::Real &  qs, amrex::Real &  gam, amrex::Real &  dqsdt, amrex::Real &  enthalpy  )

inlinestatic

                                               {
        // Local variables
        amrex::Real hltalt;       // Modified latent heat for T derivatives
 
        SatMethods::wv_sat_qsat_ice(t, p, es, qs);
 
        // For pure ice, just add latent heats.
        hltalt = lat_vap + lat_ice;
 
        enthalpy = tq_enthalpy(t, qs, hltalt);
 
        // For pure water/ice transition term is amrex::Real(0)
        deriv_outputs(t, p, es, qs, hltalt, amrex::Real(0), gam, dqsdt);
    }

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qsat_water()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE void WaterVaporSat::qsat_water ( const amrex::Real &  t, const amrex::Real &  p, amrex::Real &  es, amrex::Real &  qs, amrex::Real *  gam = nullptr, amrex::Real *  dqsdt = nullptr, amrex::Real *  enthalpy = nullptr  )

inlinestatic

                                                           {
        // Local variables
        amrex::Real hltalt;       // Modified latent heat for T derivatives
 
        SatMethods::wv_sat_qsat_water(t, p, es, qs);
 
        // "generalized" analytic expression for t derivative of es
        // accurate to within 1 percent for amrex::Real(173.16) < t < amrex::Real(373.16)
 
        no_ip_hltalt(t, hltalt);
 
        if (enthalpy)
        {
            *enthalpy = tq_enthalpy(t, qs, hltalt);
        }
 
        if (gam && dqsdt)
        {
            // For pure water/ice transition term is amrex::Real(0)
            deriv_outputs(t, p, es, qs, hltalt, amrex::Real(0), *gam, *dqsdt);
        }
    }

Referenced by findsp().

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svp_ice()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real WaterVaporSat::svp_ice ( const amrex::Real &  t )

inlinestatic

                                                  {
        return SatMethods::wv_sat_svp_ice(t);
    }

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svp_trans()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real WaterVaporSat::svp_trans ( const amrex::Real &  t )

inlinestatic

                                                    {
        return SatMethods::wv_sat_svp_trans(t);
    }

Referenced by qsat().

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svp_water()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real WaterVaporSat::svp_water ( const amrex::Real &  t )

inlinestatic

                                                    {
        return SatMethods::wv_sat_svp_water(t);
    }

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tq_enthalpy()

AMREX_GPU_HOST_DEVICE static AMREX_FORCE_INLINE amrex::Real WaterVaporSat::tq_enthalpy ( const amrex::Real &  t, const amrex::Real &  q, const amrex::Real &  hltalt  )

inlinestatic

                                                             {
        return Cp_d * t + hltalt * q;
    }

Referenced by findsp(), qsat(), qsat_ice(), and qsat_water().

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Member Data Documentation

npcf

constexpr int WaterVaporSat::npcf = 5

staticconstexpr

Referenced by calc_hltalt().

pcf

constexpr const amrex::Real WaterVaporSat::pcf[npcf]

staticconstexpr

Initial value:

= {amrex::Real(5.04469588506e-01),
                                                   -amrex::Real(5.47288442819e+00),
                                                   -amrex::Real(3.67471858735e-01),
                                                   -amrex::Real(8.95963532403e-03),
                                                   -amrex::Real(7.78053686625e-05)}

Referenced by calc_hltalt().

tmax

constexpr amrex::Real WaterVaporSat::tmax = amrex::Real(375.16)

staticconstexpr

Referenced by findsp().

tmin

constexpr amrex::Real WaterVaporSat::tmin = amrex::Real(127.16)

staticconstexpr

Referenced by findsp().

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The documentation for this class was generated from the following file:

• Source/Utils/ERF_WaterVaporSaturation.H