unit of emission rate

[yingsun1991]

The original unit of emission rate is mass unit/m3. Does anyone know how to change it to ppm?

[glenn.rolph]

Converting concentration to PPM

HYSPLIT concentrations are normally output in units of mass/volume (µg m-3, mg m-3, etc.). Emergency managers generally prefer units of parts per million (by volume) or ppm. One part per million is equal to a volume of a given gas mixed in a million volumes of air. The conversion from concentration to ppm is influenced by the temperature and pressure of the air parcel and the molecular weight of the chemical being converted.

One simplified conversion is as follows:

Cppm = pollutant concentration (µg m-3) * RT / PM
Where:
R = the universal gas constant [0.08314 hPa m3 K-1 mol-1]
T = temperature [K]
P = atmospheric pressure [hPa]
M = molecular weight of gas [g/mol]

Substituting these values into the above equation results in:

Cppm = pollutant concentration (µg m-3) * (0.08314 hPa m3 K-1 mol-1 * T) / (P * M)

and for concentration in mg m-3

Cppm = pollutant concentration (mg m-3) * (0.08314 hPa m3 K-1 mol-1 * T * 1000 ug/mg) / (P * M)

[yingsun1991]

Thanks! But more questions. Actually I'm using this model to study the transport of water vapor. Do you know how does this model deal with the background? I mean the concentration of gas such as water vapor for background. It seems that the decrease rate of the concentration is too big. For example, if I set the emission rate as 1/hr for 1 hr release. After 12 hours, the concentration will become 1E-13. It doesn't make sense.

Converting concentration to PPM

HYSPLIT concentrations are normally output in units of mass/volume (µg m-3, mg m-3, etc.). Emergency managers generally prefer units of parts per million (by volume) or ppm. One part per million is equal to a volume of a given gas mixed in a million volumes of air. The conversion from concentration to ppm is influenced by the temperature and pressure of the air parcel and the molecular weight of the chemical being converted.

One simplified conversion is as follows:

Cppm = pollutant concentration (µg m-3) * RT / PM
Where:
R = the universal gas constant [0.08314 hPa m3 K-1 mol-1]
T = temperature [K]
P = atmospheric pressure [hPa]
M = molecular weight of gas [g/mol]

Substituting these values into the above equation results in:

Cppm = pollutant concentration (µg m-3) * (0.08314 hPa m3 K-1 mol-1 * T) / (P * M)

and for concentration in mg m-3

Cppm = pollutant concentration (mg m-3) * (0.08314 hPa m3 K-1 mol-1 * T * 1000 ug/mg) / (P * M)

[shanky]

Hi yingsun1991,
I am kinda new to HYSPLIT and I am also trying to do the similar stuff using Hysplit. I wanted to simulate the source of water vapor by back-tracing the trajectory or by using the particle dispersion method. If you have done similar kind of study or anything with Water Vapor using HYSPLIT. Could you suggest me how to go about this ?

Thank You

[ariel.stein]

Background concentrations for water can be directly added to the HYSPLIT output. In general, background water concentrations can be obtained from a meteorological model.

[shanky]

Hi Ariel.stein
I have done the back-trajectory using multiple sources for the Gas (I mean I have not selected any pollutant and left all the fields to zero). While doing Advance settings for trajectory I had also included the meteorological parameters (wrf-arw model output meteorological fields). So after trajectory run finished I can plot the trajectory w.r.t. precipitation. But, I am not sure how to do the concentration plots for water vapor. Could you please suggest me how to go around it ?
Thank You

[shanky]

Hi Ariel.stein,
One more query, how to use background concentration .. I am very new to HYSPLIT .... I am trying to get familiar to the HYSPLIT. Please suggest me how to go about it.

Thank You

[ariel.stein]

Extracting the relative humidity will give you the water concentration along the path of the trajectory.

[shanky]

Hi Ariel,

I am sorry but I am still not getting you.
I have used arw2arl exec to convert the WRF-ARW output data (wrfout-d01_2013-06-10:00:00:00 to 2013-06-23 , the output has been generated for every 6 hrs interval) into the binary file which HYSPLIT can read.
My BINARY file have all the variables, but I am not sure how to do the settings of HYSPLIt in order to find out the water vapor source for my location (I have provided the lat and lon values in CONTROL file).

I am trying to do the backtracing in order to find the water vapor source.
i am using both trajectory and concentration/dispersion particle methods to get the back-tracing of water vapor in order to find the approximate location of the water vapor source. I am trying to plot the trajectory as well as the contours; I have got the trajectory as well as contour plots but I am not very sure whatever I've done is right or wrong. Could you please or suggest me how to set up the HYSPLIT ? ?

I am attaching herewith the trajectory SETUP.CGF and defauth_traj files
&SETUP
tratio = 0.75,
mgmin = 10,
khmax = 9999,
kmixd = 0,
kmsl = 0,
nstr = 0,
mhrs = 9999,
nver = 0,
tout = 360,
tm_tpot = 1,
tm_tamb = 1,
tm_rain = 1,
tm_mixd = 1,
tm_relh = 1,
tm_sphu = 1,
tm_mixr = 1,
tm_dswf = 0,
tm_terr = 0,
dxf = 1.0,
dyf = 1.0,
dzf = 0.01,

##### default_traj
13 06 22 00
30
51.55 -113.10 600.0
51.45 -113.60 600.0
51.35 -113.95 600.0
51.20 -114.10 600.0
50.07 -115.00 600.0
50.14 -114.60 600.0
50.21 -114.20 600.0
50.28 -113.80 600.0
50.35 -113.50 600.0
50.43 -113.10 600.0
50.50 -112.79 600.0
50.57 -112.45 600.0
50.65 -112.15 600.0
50.73 -111.95 600.0
50.80 -111.80 600.0
50.90 -111.60 600.0
49.00 -115.00 600.0
49.07 -114.60 600.0
49.14 -114.20 600.0
49.21 -113.80 600.0
49.28 -113.50 600.0
49.35 -113.10 600.0
49.43 -112.80 600.0
49.50 -112.45 600.0
49.58 -112.15 600.0
49.67 -111.95 600.0
49.79 -111.80 600.0
49.89 -111.60 600.0
48.95 -114.20 600.0
48.75 -113.80 600.0
-180
0
10000.0
1
/glade/u/home/kurkute/hysplit/trunk/working.782/
wrf_new_d01
./
tdump

As well as my CONTROL file for concentration is as follows:
13 06 22 00
30
51.55 -113.10 600.0
51.45 -113.60 600.0
51.35 -113.95 600.0
51.20 -114.10 600.0
50.07 -115.00 600.0
50.14 -114.60 600.0
50.21 -114.20 600.0
50.28 -113.80 600.0
50.35 -113.50 600.0
50.43 -113.10 600.0
50.50 -112.79 600.0
50.57 -112.45 600.0
50.65 -112.15 600.0
50.73 -111.95 600.0
50.80 -111.80 600.0
50.90 -111.60 600.0
49.00 -115.00 600.0
49.07 -114.60 600.0
49.14 -114.20 600.0
49.21 -113.80 600.0
49.28 -113.50 600.0
49.35 -113.10 600.0
49.43 -112.80 600.0
49.50 -112.45 600.0
49.58 -112.15 600.0
49.67 -111.95 600.0
49.79 -111.80 600.0
49.89 -111.60 600.0
48.95 -114.20 600.0
48.75 -113.80 600.0
-180
0
10000.0
1
/glade/u/home/kurkute/hysplit/trunk/working.782/
wrf_new_d01
1
Water_Vapor
1.0
1.0
00 00 00 00 00
1
51.0 -115.0
0.05 0.05
30.0 40.0
./
cdump
1
500
00 00 00 00 00
00 00 00 00 00
00 180 00
1
0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0
0.0
0.0

And the CONC.CFG or SETUP file is as follows:
&SETUP
tratio = 0.75,
delt = 0.0,
initd = 0,
kpuff = 0,
khmax = 9999,
khinp = 0,
numpar = 50000,
maxpar = 100000,
nbptyp = 1,
qcycle = 0.0,
efile = '',
k10m = 1,
kdef = 0,
krand = 2,
kzmix = 0,
kbls = 1,
kblt = 0,
isot = -99,
vscale = 200.0,
vscales = 200.0,
vscaleu = 200.0,
hscale = 10800.0,
capemin = -1.0,
tvmix = 1.00,
tkerd = 0.18,
tkern = 0.18,
kmix0 = 250,
kmixd = 0,
ninit = 1,
ndump = 0,
ncycl = 0,
pinbc = 'PARINBC',
pinpf = 'PARINIT',
poutf = 'PARDUMP',
messg = 'MESSAGE',
vdist = 'VMSDIST',
mgmin = 10,
conage = 48,
kmsl = 0,
kwet = 1,
ichem = 0,
cpack = 1,
cmass = 0,
kspl = 1,
krnd = 6,
frhmax = 3.00,
splitf = 1.00,
frhs = 1.00,
frvs = 0.01,
frts = 0.10,
dxf = 1.00,
dyf = 1.00,
dzf = 0.01,
/

Thank You very Much

[ariel.stein]

I think you are in the right track. I would suggest you explore the possibility of using the concept of footprints to get an idea of the water sources that influence your measurements.
Below you can find a brief description of this capability in HYSPLIT. However, I would suggest you find out more about water source attribution in the literature.

The STILT model is a variation of HYSPLIT developed by Lin et al. (2003 - JGR, VOL. 108, NO. D16, 4493, doi:10.1029/2002JD003161) that can be used to estimate upwind surface fluxes from atmospheric measurements. Although HYSPLIT does not contain the mass conservation adjustments and coupled vertical-mixing horizontal- transport features of STILT, setting this flag causes the HYSPLIT concentration output field units to be similar to the STILT configuration. Two changes are introduced; the mass summation is divided by air density resulting in a mixing ratio output field (ICHEM=6) and the lowest concentration summation layer (concentration layer top depth) is permitted to vary with the mixed layer depth (ICHEM=9), so that only particles below 50% of the mixed layer depth at each time step are summed to the lowest layer. The ICHEM=8 switch turns on both density and varying layer depth. A text file of particle position information (PARTICLE.DAT) at each time step will also be created unless the namelist parameter OUTDT defining the output interval (min) is changed.