2023/02/16 JAXA/IRAP Kickoff meeting
Contacts
IRAP
ISAS/JAXA
-
Go Murakami
-
Sae Azawa
ISEE/Nagoya University
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Yoshizumi Miyoshi <miyoshi@isee.nagoya-u.ac.jp>
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Tomo Hori (MIO Science Center)
Related documents
MEA Datasets description
File naming
We will use the file naming pattern recommanded in ISAS Wiki:
mmo_mmpe-mea[12]_<dataset>_yyyymmdd_vM.n.cdfWe have 2 sensors (mppe-mea1, mppe-mea2) and will deliver separate CDF files for each one.
CDF version
We will use the recommandation found in ISAS Wiki:
-
M (major version)
will be defined, for each dataset as follow:
0: Preliminary or test-purpose dataset definition
1..n: official releases, incremented each time the definition of a dataset is modified
When a CDF variable is added/modified/deleted
-
n (minor version)
will be incremented (starting from 0 for each major version of a dataset) for each reprocessing of a daily file
L1 datasets
| Dataset | Description |
|---|---|
mmo_mppe-mea[12]_l1_vm-[low, hig] |
Onboard moments |
mmo_mppe-mea[12]_l1_3D-[low,med,hig] |
MEA 3D data |
mmo_mppe-mea[12]_l1_hsk |
Housekeeping |
mmo_mppe-mea[12]_l1_omni-[16e,32e,64e] |
Omni-directional (1D) data |
mmo_mppe-mea[12]_l1_pap-[2s,4s,16s] |
Pitch-angle data |
|
not all the datasets will be delivered during the cruise phase (instrument not spinned) |
L2 datasets
| Dataset | Description |
|---|---|
mmo_mppe-mea[12]_l2_vm-[low, hig] |
Moments |
mmo_mppe-mea[12]_l2_3D-[low,med,hig]-[unit] |
MEA 3D data |
mmo_mppe-mea[12]_l2_omni-[unit]-[16e,32e,64e] |
Omni-directional (1D) data |
mmo_mppe-mea[12]_l2_pap-[unit]-[2s,4s,16s] |
Pitch-angle data |
This is a preliminary list of our L2 datasets, subject to changes
Time-series datasets
All MEA datasets are organized as a time-serie with a main CDF time variable (epoch)
The epoch variable correspond to a CDF_TT2000 variable.
epoch : CDF_TT2000
- CATDESC : Center/start of acquisition interval (dataset level depending)
- FIELDNAM : epoch
- FILLVAL : 9999-12-31 23:59:59.999999
- LABLAXIS : epoch
- UNITS : ns
- VALIDMIN : 1990-01-01 00:00:00
- VALIDMAX : 2029-12-31 23:59:58.999000
- VAR_TYPE : support_data
- SCALETYP : linear
- MONOTON : INCREASE
- TIME_BASE : J2000
- TIME_SCALE : Terrestrial Time
- REFERENCE_POSITION : Rotating Earth Geoid
- ...MEA L1 datasets
MEA L1 datasets are currently timetagged at the start of acquisition interval
Currently, the epoch is defined with the following attributes:
- DELTA_PLUS_VAR : duration (or delta_epoch)And duration a CDF variable, record-varying, whose DEPEND_0 = epoch, whose value is given in data records (curently ~4s)
duration : CDF_REAL4
- CATDESC : Interval duration
- DEPEND_0 : epoch
- LABLAXIS : Duration
- UNITS : s|
|
we can rename the duration variable as delta_epoch if required. |
MEA L2 datasets
MEA2 L2 datasets will be timetagged at the center of acquisition interval
- DELTA_PLUS_VAR : delta_epoch
- DELTA_MINUS_VAR : delta_epochWith delta_epoch a CDF variable defined as follow:
delta_epoch : FLOAT
- CATDESC : Half-interval duration
- DEPEND_0 : epoch
- LABLAXIS : Duration
- UNITS : s|
|
we don’t think useful to use delta_epoch1 and delta_epoch2 as indicated in ISAS wiki, as the 2 variables will have by definition the same values. |
Internal clock
We will also give the value of internal clock, defined as mdp_TI in ISAS Wiki.
TI0 : (18352,) x CDF_UINT4
- CATDESC : TI0
- DEPEND_0 : Epoch
- LABLAXIS : TI0
- VALIDMIN : 0.0
- VALIDMAX : 4294970000.0
- SCALETYP : linearThis variable is currently named TI0 in our L1 datasets, but we can renamed as mdp_TI if required by the project.
CDF variables description
Record varying variables
All record-varying variable will have the following attribute:
- DEPEND_0 = epochMulti-dimensional variables
All multi-dimensional variables may use DEPEND_i attributes to describe their corresponding axis.
3D_counts : (records x 8 x 16 x 16) x CDF_UINT2
- CATDESC : 3D counts
- DEPEND_0 : Epoch
- DEPEND_1 : channels
- DEPEND_2 : sectors
- DEPEND_3 : energypolar/azimuthal bins
There are linearly spaced.
We give the N central position (in instrument reference frame) and delta_plus/delta_minus resolution.
channels : (8,) x CDF_REAL4
- CATDESC : Channels (anodes)
- FIELDNAM : Channels (anodes)
- LABLAXIS : channels
- VAR_TYPE : support_data
- SCALETYP : linear
- UNITS : degree
- DELTA_PLUS : 11.25
- DELTA_MINUS : 11.25sectors : (16,) x CDF_REAL4
- CATDESC : Azimuthal bins
- FIELDNAM : Aziuthal bins
- LABLAXIS : sectors
- SCALETYP : linear
- UNITS : degree
- DELTA_PLUS : 11.25
- DELTA_MINUS : 11.25|
|
These variable are non record-varying. |
energy tables
We are using logarithmic energy tables, so we have to give the N central values, N delta_plus and N delta_minus values.
energy : (records x 16) x CDF_REAL4
- CATDESC : energy
- DEPEND_0 : Epoch
- LABLAXIS : energy
- VAR_TYPE : support_data
- SCALETYP : log
- DELTA_PLUS : energy_delta_plus
- DELTA_MINUS : energy_delta_minus
energy_delta_plus : (records x 16) x CDF_REAL4
- CATDESC : energy_delta_plus
- DEPEND_0 : Epoch
- LABLAXIS : energy_delta_plus
- VAR_TYPE : support_data
- SCALETYP : log
energy_delta_minus : (records x 16) x CDF_REAL4
- CATDESC : energy_delta_minus
- DEPEND_0 : Epoch
- LABLAXIS : energy_delta_minus
- VAR_TYPE : support_data
- SCALETYP : log|
|
In our energy dependent datasets, the energy table may change during the day. So, we have no more choice than make the energy table record-varying, and give the values in each data record. |
Examples
We can provide an example of MEA1 omni-directional dataset for 2022/12/25.
You can find a CDF file and corresponding metadata (.txt) for both L1 and L2 data.
MEA1 L1 omni dataset
Other points
spice kernels
Is JAXA planning to use spice kernels after the separation ?
-
mdp TI to UTC conversion
-
conversion from instrument reference frame ⇒ SC reference frame ⇒ MSO
PDS4 metadata requirements
It was decided that PI teams deliver l1p data to Jaxa that will convert to L2 CDFs and deliver to PDS
We would prefer to prepare MEA L2 CDF files at IRAP and deliver files with the most possible complete metadata.
We can agree to include specific PDS metadata or let JAXA include them before final delivery to PDS archive.
