Reading ADAPT FITS Files

This example demonstrates how to load data from the Air Force Data Assimilative Photospheric Flux Transport (ADAPT) model into a list of sunpy.map.Map objects.

import matplotlib.pyplot as plt

import astropy.units as u
from astropy.io import fits

import sunpy.map
from sunpy.coordinates.sun import carrington_rotation_time
from sunpy.net import Fido
from sunpy.net import attrs as a

First we will download an ADAPT FITS file. To do this we will use the sunpy.net.Fido search interface to search for ADAPT data for Carrington Rotation 2193, and the first longitude type (0) which means the data will be in a Carrington coordinate frame.

date_start = carrington_rotation_time(2193)
date_end = date_start + 6*u.h

result = Fido.search(a.Time(date_start, date_end), a.Instrument('adapt'), a.adapt.ADAPTLonType("0"))
print(result)

downloaded_file = Fido.fetch(result)

Results from 1 Provider:

1 Results from the ADAPTClient:

       Start Time               End Time        Instrument Provider Source ADAPTFileType ADAPTLonType ADAPTInputSource ADAPTDataAssimilation ADAPTResolution ADAPTVersionYear ADAPTRealizations ADAPTVersionMonth ADAPTEvolutionMode ADAPTHelioData ADAPTMagData days_since_last_obs hours_since_last_obs minutes_since_last_obs seconds_since_last_obs
----------------------- ----------------------- ---------- -------- ------ ------------- ------------ ---------------- --------------------- --------------- ---------------- ----------------- ----------------- ------------------ -------------- ------------ ------------------- -------------------- ---------------------- ----------------------
2017-07-20 08:00:00.000 2017-07-20 08:00:59.999      ADAPT      NSO   GONG             4            0                3                     1               1                3                12                 k                  i              n            1                   0                    1                     56                      0

ADAPT FITS files contain 12 realizations of synoptic magnetogram output as a result of varying model assumptions. This is explained in detail in this talk.

Because the array in the FITS file is 3D, it cannot be passed directly to sunpy.map.Map, as this will take the first slice only, ignoring the other realizations. Instead, we’ll open the FITS file with astropy.io.fits and manually pull out each model realization.

adapt_fits = fits.open(downloaded_file[0])

adapt_fits is a list of HDU objects. The first of these contains the 12 realizations of the data and a header with sufficient information to build a list of maps. We unpack this information into a list of (data, header) tuples where data are the different adapt realizations.

data_header_pairs = [(map_slice, adapt_fits[0].header) for map_slice in adapt_fits[0].data]

Next, pass this list of tuples to sunpy.map.Map to make a list of maps:

adapt_maps = sunpy.map.Map(data_header_pairs)

adapt_maps is now a list of our individual adapt realizations. Here, we generate a static plot accessing a subset of the individual maps in turn.

fig = plt.figure(figsize=(5, 10), layout='constrained')
for i, a_map in enumerate(adapt_maps[::4]):
    ax = fig.add_subplot(3, 1, i+1, projection=a_map)
    ax.tick_params(axis='x', labelsize=6)
    im = a_map.plot(axes=ax, cmap='bwr', vmin=-50, vmax=50, title=f"Realization {1+i*4:02d}")

fig.colorbar(im, label='Magnetic Field Strength [G]', orientation='horizontal')

plt.show()

INFO: Missing metadata for solar radius: assuming the standard radius of the photosphere. [sunpy.map.mapbase]
/home/docs/checkouts/readthedocs.org/user_builds/sunpy/conda/stable/lib/python3.12/site-packages/sunpy/map/mapbase.py:683: SunpyMetadataWarning: Missing metadata for observer: assuming Earth-based observer.
For frame 'heliographic_stonyhurst' the following metadata is missing: dsun_obs,hglt_obs,hgln_obs
For frame 'heliographic_carrington' the following metadata is missing: crlt_obs,dsun_obs,crln_obs

  obs_coord = self.observer_coordinate
INFO: Missing metadata for solar radius: assuming the standard radius of the photosphere. [sunpy.map.mapbase]
/home/docs/checkouts/readthedocs.org/user_builds/sunpy/conda/stable/lib/python3.12/site-packages/sunpy/map/mapbase.py:683: SunpyMetadataWarning: Missing metadata for observer: assuming Earth-based observer.
For frame 'heliographic_stonyhurst' the following metadata is missing: dsun_obs,hglt_obs,hgln_obs
For frame 'heliographic_carrington' the following metadata is missing: crlt_obs,dsun_obs,crln_obs

  obs_coord = self.observer_coordinate
INFO: Missing metadata for solar radius: assuming the standard radius of the photosphere. [sunpy.map.mapbase]
/home/docs/checkouts/readthedocs.org/user_builds/sunpy/conda/stable/lib/python3.12/site-packages/sunpy/map/mapbase.py:683: SunpyMetadataWarning: Missing metadata for observer: assuming Earth-based observer.
For frame 'heliographic_stonyhurst' the following metadata is missing: dsun_obs,hglt_obs,hgln_obs
For frame 'heliographic_carrington' the following metadata is missing: crlt_obs,dsun_obs,crln_obs

  obs_coord = self.observer_coordinate