NRLMSISE-00 initial C release

C source code for the NRLMSISE-00 empirical atmosphere model

The NRLMSIS-00 (sic!) empirical atmosphere model was developed
by Mike Picone, Alan Hedin, and Doug Drob. It describes the
neutral temperature and densities in Earth's atmosphere from
ground to thermospheric heights.

(quoted from http://modelweb.gsfc.nasa.gov/ ) - you can find
a longer explanation of this model there, too.

The authors of NRLMSISE-00 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.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Please
inform the maintainer of the C release (Dominik Brodowski -
mail@brodo.de) of any patches and bug-fixes you implement for
NRLMSISE-00 so that this C package can be updated with these
improvements.

Signed-off-by: Dominik Brodowski <linux@dominikbrodwski.net>

1 files changed, 222 insertions, 0 deletions

diff --git a/nrlmsise-00.h b/nrlmsise-00.h
new file mode 100644
index 0000000..842a4b0
--- /dev/null
+++ b/nrlmsise-00.h
@@ -0,0 +1,222 @@
+/* -------------------------------------------------------------------- */
+/* ---------  N R L M S I S E - 0 0    M O D E L    2 0 0 1  ---------- */
+/* -------------------------------------------------------------------- */
+
+/* This file is part of the NRLMSISE-00  C source code package - release
+ * 20020305
+ *
+ * The NRLMSISE-00 model was developed by Mike Picone, Alan Hedin, and
+ * Doug Drob. They also wrote a NRLMSISE-00 distribution package in 
+ * FORTRAN which is available at
+ * http://uap-www.nrl.navy.mil/models_web/msis/msis_home.htm
+ *
+ * Dominik Brodowski implemented and maintains this C version. You can
+ * reach him at devel@brodo.de. See the file "DOCUMENTATION" for details,
+ * and check http://www.brodo.de/english/pub/nrlmsise/index.html for
+ * updated releases of this package.
+ */
+
+
+
+/* ------------------------------------------------------------------- */
+/* ------------------------------- INPUT ----------------------------- */
+/* ------------------------------------------------------------------- */
+
+struct nrlmsise_flags {
+	int switches[24];
+	double sw[24];
+	double swc[24];
+};
+/*   
+ *   Switches: to turn on and off particular variations use these switches.
+ *   0 is off, 1 is on, and 2 is main effects off but cross terms on.
+ *
+ *   Standard values are 0 for switch 0 and 1 for switches 1 to 23. The 
+ *   array "switches" needs to be set accordingly by the calling program. 
+ *   The arrays sw and swc are set internally.
+ *
+ *   switches[i]:
+ *    i - explanation
+ *   -----------------
+ *    0 - output in centimeters instead of meters
+ *    1 - F10.7 effect on mean
+ *    2 - time independent
+ *    3 - symmetrical annual
+ *    4 - symmetrical semiannual
+ *    5 - asymmetrical annual
+ *    6 - asymmetrical semiannual
+ *    7 - diurnal
+ *    8 - semidiurnal
+ *    9 - daily ap [when this is set to -1 (!) the pointer
+ *                  ap_a in struct nrlmsise_input must
+ *                  point to a struct ap_array]
+ *   10 - all UT/long effects
+ *   11 - longitudinal
+ *   12 - UT and mixed UT/long
+ *   13 - mixed AP/UT/LONG
+ *   14 - terdiurnal
+ *   15 - departures from diffusive equilibrium
+ *   16 - all TINF var
+ *   17 - all TLB var
+ *   18 - all TN1 var
+ *   19 - all S var
+ *   20 - all TN2 var
+ *   21 - all NLB var
+ *   22 - all TN3 var
+ *   23 - turbo scale height var
+ */
+
+struct ap_array {
+	double a[7];   
+};
+/* Array containing the following magnetic values:
+ *   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 
+ */
+
+
+struct nrlmsise_input {
+	int year;      /* year, currently ignored */
+	int doy;       /* day of year */
+	double sec;    /* seconds in day (UT) */
+	double alt;    /* altitude in kilometes */
+	double g_lat;  /* geodetic latitude */
+	double g_long; /* geodetic longitude */
+	double lst;    /* local apparent solar time (hours), see note below */
+	double f107A;  /* 81 day average of F10.7 flux (centered on doy) */
+	double f107;   /* daily F10.7 flux for previous day */
+	double ap;     /* magnetic index(daily) */
+	struct ap_array *ap_a; /* see above */
+};
+/*
+ *   NOTES ON INPUT VARIABLES: 
+ *      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.
+ */
+
+
+
+/* ------------------------------------------------------------------- */
+/* ------------------------------ OUTPUT ----------------------------- */
+/* ------------------------------------------------------------------- */
+
+struct nrlmsise_output {
+	double d[9];   /* densities */
+	double t[2];   /* temperatures */
+};
+/* 
+ *   OUTPUT VARIABLES:
+ *      d[0] - HE NUMBER DENSITY(CM-3)
+ *      d[1] - O NUMBER DENSITY(CM-3)
+ *      d[2] - N2 NUMBER DENSITY(CM-3)
+ *      d[3] - O2 NUMBER DENSITY(CM-3)
+ *      d[4] - AR NUMBER DENSITY(CM-3)                       
+ *      d[5] - TOTAL MASS DENSITY(GM/CM3) [includes d[8] in td7d]
+ *      d[6] - H NUMBER DENSITY(CM-3)
+ *      d[7] - N NUMBER DENSITY(CM-3)
+ *      d[8] - Anomalous oxygen NUMBER DENSITY(CM-3)
+ *      t[0] - EXOSPHERIC TEMPERATURE
+ *      t[1] - TEMPERATURE AT ALT
+ * 
+ *
+ *      O, H, and N are set to zero below 72.5 km
+ *
+ *      t[0], Exospheric temperature, is set to global average for
+ *      altitudes below 120 km. The 120 km gradient is left at global
+ *      average value for altitudes below 72 km.
+ *
+ *      d[5], TOTAL MASS DENSITY, is NOT the same for subroutines GTD7 
+ *      and GTD7D
+ *
+ *        SUBROUTINE GTD7 -- d[5] is the sum of the mass densities of the
+ *        species labeled by indices 0-4 and 6-7 in output variable d.
+ *        This includes He, O, N2, O2, Ar, H, and N but does NOT include
+ *        anomalous oxygen (species index 8).
+ *
+ *        SUBROUTINE GTD7D -- d[5] is the "effective total mass density
+ *        for drag" and is the sum of the mass densities of all species
+ *        in this model, INCLUDING anomalous oxygen.
+ */
+
+
+
+/* ------------------------------------------------------------------- */
+/* --------------------------- PROTOTYPES ---------------------------- */
+/* ------------------------------------------------------------------- */
+
+/* GTD7 */
+/*   Neutral Atmosphere Empircial Model from the surface to lower
+ *   exosphere.
+ */
+void gtd7 (struct nrlmsise_input *input, \
+           struct nrlmsise_flags *flags, \
+           struct nrlmsise_output *output);
+
+
+/* GTD7D */
+/*   This subroutine provides Effective Total Mass Density for output
+ *   d[5] which includes contributions from "anomalous oxygen" which can
+ *   affect satellite drag above 500 km. See the section "output" for
+ *   additional details.
+ */
+void gtd7d(struct nrlmsise_input *input, \
+           struct nrlmsise_flags *flags, \
+           struct nrlmsise_output *output);
+
+
+/* GTS7 */
+/*   Thermospheric portion of NRLMSISE-00
+ */
+void gts7 (struct nrlmsise_input *input, \
+	   struct nrlmsise_flags *flags, \
+	   struct nrlmsise_output *output);
+
+
+/* GHP7 */
+/*   To specify outputs at a pressure level (press) rather than at
+ *   an altitude.
+ */
+void ghp7 (struct nrlmsise_input *input, \
+           struct nrlmsise_flags *flags, \
+           struct nrlmsise_output *output, \
+           double press);
+
+
+
+/* ------------------------------------------------------------------- */
+/* ----------------------- COMPILATION TWEAKS ------------------------ */
+/* ------------------------------------------------------------------- */
+
+/* "inlining" of functions */
+/*   Some compilers (e.g. gcc) allow the inlining of functions into the
+ *   calling routine. This means a lot of overhead can be removed, and
+ *   the execution of the program runs much faster. However, the filesize
+ *   and thus the loading time is increased.
+ */
+#ifdef INLINE
+#define __inline_double inline double
+#else
+#define __inline_double double
+#endif