NRLMSISE-00 for Node.js

The NRLMSIS-00 empirical atmosphere model was developed by Mike Picone, Alan Hedin, and Doug Drob based on the MSISE90 model.

Background

The authors of the NRLMSISE-00 model have released a FORTRAN version which is available at http://uap-www.nrl.navy.mil/models_web/msis/msis_home.htm Based on the Official Beta Release 1.0 (NRLMSISE-00.DIST12.TXT) Dominik Brodowski wrote an implementation in C which is available on http://www.brodo.de/english/pub/nrlmsise/ . This release is based on the Official Beta Release 2.0 Based on the C version, this Node port was created using source C files can be found at git://git.linta.de/~brodo/nrlmsise-00.git . The C port was converted to C++ and compiled into a NodeJS module using N-API.

The MSISE90 model describes the neutral temperature and densities in Earth's atmosphere from ground to thermospheric heights. Below 72.5 km the model is primarily based on the MAP Handbook (Labitzke et al., 1985) tabulation of zonal average temperature and pressure by Barnett and Corney, which was also used for the CIRA-86. Below 20 km these data were supplemented with averages from the National Meteorological Center (NMC). In addition, pitot tube, falling sphere, and grenade sounder rocket measurements from 1947 to 1972 were taken into consideration. Above 72.5 km MSISE-90 is essentially a revised MSIS-86 model taking into account data derived from space shuttle flights and newer incoherent scatter results. For someone interested only in the thermosphere (above 120 km), the author recommends the MSIS-86 model. MSISE is also not the model of preference for specialized tropospheric work. It is rather for studies that reach across several atmospheric boundaries. (quoted from http://nssdc.gsfc.nasa.gov/space/model/atmos/nrlmsise00.html)

Installation and testing

$ npm install
$ npm run install
$ npm run test

Usage example

let Nrlmsise=require("nrlmsise");

let n=new Nrlmsise();

n.doy=172;		/* day of year */
n.year=0; 		/* year, currently ignored */
n.sec=29000;	/* seconds in day (UT) */
n.alt=400;		/* altitude in kilometers */
n.g_lat=60;		/* geodetic latitude */
n.g_long=-70;	/* seconds in day (UT) */
n.lst=16;		/* local apparent solar time (hours), see note below */
n.f107A=150;	/* 81 day average of F10.7 flux (centered on doy) */
n.f107=150;		/* daily F10.7 flux for previous day */
n.ap=4;			/* magnetic index(daily) */
n.switches=[0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1];	// Actually unnecessary, since this is the default.  We could also use n.set_switch(n, val)

console.log(JSON.stringify(n.gtd7()));

output:

{
  "HE": 666517.690495152,
  "O": 113880555.97522168,
  "N2": 19982109.255734544,
  "O2": 402276.3585712511,
  "AR": 3557.464994515886,
  "total": 4.074713532757222e-15,
  "H": 34753.12399717142,
  "N": 4095913.2682930017,
  "anomalous_oxygen": 26672.73209335869,
  "d": [
    666517.690495152,
    113880555.97522168,
    19982109.255734544,
    402276.3585712511,
    3557.464994515886,
    4.074713532757222e-15,
    34753.12399717142,
    4095913.2682930017,
    26672.73209335869
  ],
  "exospheric_temperature": 1250.5399435607994,
  "temperature": 1241.4161300191206,
  "t": [
    1250.5399435607994,
    1241.4161300191206
  ]
}

Notes on input variables (from nrlmsise-00.h):

UT, Local Time, and Longitude are used independently in the model and are not of equal importance for every situation. For the most physically realistic calculation these three variables should be consistent (lst=sec/3600 + g_long/15). The Equation of Time departures from the above formula for apparent local time can be included if available but are of minor importance. f107 and f107A values used to generate the model correspond to the 10.7 cm radio flux at the actual distance of the Earth from the Sun rather than the radio flux at 1 AU. The following site provides both classes of values: ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SOLAR_RADIO/FLUX/ f107, f107A, and ap effects are neither large nor well established below 80 km and these parameters should be set to 150., 150., and 4. respectively.

Notes

do not try to set switches directly, it won't work.

nrlmsise.switches[5]=0;						// Error
nrlmsise.set_switch(5,0);					// Do this instead
nrlmsise.switches=[1,2,3,4 /* ,... */, 24]; // or this

gt7d() is not implemented - send me a message if you would like it added, I just haven't done it yet...

Code documentation

Nrlmsise

NRLMSISE-00 for Node.js

Kind: global class

• Nrlmsise
  • .ap
  • .doy
  • .year
  • .sec
  • .alt
  • .g_lat
  • .g_long
  • .lst
  • .f107A
  • .f107
  • .ap ⇒ Number
  • .doy ⇒ Number
  • .year ⇒ Number
  • .sec ⇒ Number
  • .alt ⇒ Number
  • .g_lat
  • .g_long ⇒ Number
  • .lst ⇒ Number
  • .f107A ⇒ Number
  • .f107 ⇒ Number
  • .ap_a
  • .switches
  • .set_switch(n, val)
  • .set_paramter(name, val)
  • .get_paramter(name) ⇒ Number

nrlmsise.ap

Set daily magnetic index

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.doy

Set day of year

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.year

Set year (currently ignored)

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.sec

Set seconds in day (UT)

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.alt

Set altitude (km)

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.g_lat

Set geodetic latitude

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.g_long

Set geodetic longitude

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.lst

Set lst, the local apparent solar time (hours)

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.f107A

Set f107A, the 81 day average of F10.7 flux (centered on doy)

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.f107

Set f107, the daily F10.7 flux for previous day

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value to set. |

nrlmsise.ap ⇒ Number

Get daily magnetic index

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.doy ⇒ Number

Get day of year

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.year ⇒ Number

Get year (currently ignored)

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.sec ⇒ Number

Get seconds in day (UT)

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.alt ⇒ Number

Get altitude (km)

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.g_lat

Get geodetic latitude

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Number | the value |

nrlmsise.g_long ⇒ Number

Get geodetic longitude

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.lst ⇒ Number

Get lst, the local apparent solar time (hours)

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.f107A ⇒ Number

Get f107A, the 81 day average of F10.7 flux (centered on doy)

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.f107 ⇒ Number

Get f107, the daily F10.7 flux for previous day

Kind: instance property of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

nrlmsise.ap_a

Set AP array

Set the AP array containing the following magneticvalues: 0 : daily AP 1 : 3 hr AP index for current time 2 : 3 hr AP index for 3 hrs before current time 3 : 3 hr AP index for 6 hrs before current time 4 : 3 hr AP index for 9 hrs before current time 5 : Average of eight 3 hr AP indicies from 12 to 33 hrs prior to current time 6 : Average of eight 3 hr AP indicies from 36 to 57 hrs prior to current time

Note this will automatically set switch 9 to -1. If you go back to an individual AP value, you must manually reset this switch.

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Array | the ap array to set. Array must contain 7 numbers. Values are copied. |

nrlmsise.switches

Set switches

Kind: instance property of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | val | Array | the array to set. Array must contain exactly 24 numbers. Values are copied. |

nrlmsise.set_switch(n, val)

Set a switch

Kind: instance method of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | n | Number | the switch index, [0..23] | | val | Number | the value to set |

nrlmsise.set_paramter(name, val)

Set a parameter

Kind: instance method of Nrlmsise
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | name | String | the name | | val | Number | the value to set |

nrlmsise.get_paramter(name) ⇒ Number

Get a parameter

Kind: instance method of Nrlmsise
Returns: Number - val the value
Throws:

• Error e error on error

| Param | Type | Description | | --- | --- | --- | | name | String | the name |