grace | bundle

Tools for manipulating and analysing GRACE level-2 data

balaji devaraju
devaraju at ife uni-hannover de

Functions for rearranging the SH coefficients

klm2sc Rearranges the output of KLMTSRSMAT back in the format provided by READGRC
klmtsrsmat Rearranges the GRACE SH coefficients in order to perform time-series analysis.
prpfltr Arranges the filter matrices in the required format (required by MASSESTMTR).
colombo Arranging [l m Clm Slm] in order-leading format
colomboQ Arranging a filter/covariance matrix in order-leading format
degordrngvec Arranging [l m Clm Slm] in degree-leading format
degordrngQ Arranging a filter/covariance matrix in degree-leading format
vcm2vec Extract the diagonal elements of a degree-leading filter/covariance matrix and arrange it in [l m Clm Slm] format

Rotation of filter matrices

rotklmRotating an SH spectrum of a field to a given location
rotspkcovRotating the spectrum of a filter to the desired location

Power spectrum

degvarSame as SHbundle/degreeinfo but only provides degree variances

Time-series analysis

lombscarglePeriodogram analysis of time-series (spectrum and space).
lssaLeast-squares spectral analysis of time-series.
intannumGives information about longest contiguous part of the time-series.
monthfixFills data gaps in the time-series with NaN values.

Calendar Utilities

daysinmonth Provides the number of days in a month depending on the year.
daysinyear Provides the number of days in the year.
dayofyear Provides the day of the year for a given date.
doymonth Provides the month for a given day of the year
doy2cal Provides calendar date for a given day of the year
grctimetag Provides the appropriate time-tag in days for every GRACE monthly solution.
isleap Determines if a given year is a leap year or not
monthnames Provides names of months in different formats

GRACE data specific functions

I/O functions
readgrace Read GRACE SH coefficients provided in text files by CSR,GFZ and JPL in ICGEM format
rdslrc20 Read SLR C20 values from technical note 7
readgrccov Read GRACE variance-covariance matrices provided on request by GFZ
Compute from GRACE SH data
dealias Tide de-aliasing of GRACE time-series of coefficients as well as grid points
detrendgrc De-trending the GRACE coefficients as well as grid points
getgracemean Computes the mean of the SH data given a start and end date
massestmtr Converts GRACE time-series of SH coefficients to spatial grids
monthlyres Computes the difference between the time-series and its mean-annual cycle.
remgracemonths Removes GRACE months that are regularized and are flagged '2' by GFZ

Simulating GRACE normal matrices

NOTE: The following programs require the GRACE L1b position data.

blddsgn Build the design matrix for computing the GRACE normal matrices
blockinv Block inversion of GRACE normal matrices via Schur complement method
grcnrml Simulates the normal matrix for a GRACE monthly solution.
grccvrnc Wrapper function for GRCNRML to simulate covariance matrices recursively for the whole time-series.
prpcoord Prepares GRACE-A GRACE-B positions for GRCNRML

Functions for computing catchment specific quantities

catchagg Aggregates mass values over a given catchments.
catchleak Computes the leakage into all the catchments for a given filter.
catchtsrs Rearranges the aggregated mass values from MASSESTMTR for performing time-series analysis.
cindxcoord Provides the coordinates of the pixels of a given catchment.
ctchmntcov Propagates the GRACE covariance to the catchments.
ctchmntdsgn Provides a spherical harmonic design matrix for the aggregated catchments.
fillcatch Fill a particular catchment pixels with a given value.
findindx Retrieves time-series of specified catchments.

Data required for catchment specific quantities

ctchnms.mat MAT-file containing the catchment names, their area and identification numbers.
ctchmntindx.mat MAT-file containing the catchment boundaries in a 0.5 x 0.5 degree raster grid.
ctchmntindx3.mat Same as ctchmntindx.mat but includes Greenland and Antarctica.

Homogeneous isotropic filters

bttrwrth Butterworth filter defined for the spectrum
diffusionfil Diffusion filter
gaussian Gaussian filter
gaussfltr Replacement for gaussian. Uses numerical quadrature
instead of recursion formula
pellinen Pellinen coefficients of the box-car filter on the sphere
spkcosine Spectral cosine filter
sptbttrwrth Spatial Butterworth filter
sptcosine Spatial cosine filter
sptgauss Generates the spatial weights of the Gaussian filter directly.
vonhann von Hann filter (2nd order spatial cosine filter)

Inhomogeneous anisotropic filters

hannoniso Anisotropic Gaussian filter proposed by S-C Han et al 2005
fanfilter Anisotropic filter named 'Fan' designed by Zhang et al 2009
dstrpngmtrx Destriping filter of Swenson & Wahr 2006

Legendre transform: Synthesis & Analysis

spt2spk Analysis function for the Legendre transform
spk2spt Synthesis function for the Legendre transform

Performance analysis of filters

anifperf Analyses the performance of inhomgeneous (an)isotropic filters
isofperf Analyses the performance of homogeneous isotropic filters
hisospvar Spatial variance of the homogeneous isotropic filters
mtfhiso Modulation transfer function of the homogeneous isotropic filters

Visualization tools

mapfield Maps a grid of mass estimates or other quantities.
sctriplot Plots the spherical harmonic coefficients as a triangle (SC-format).
tsplot Plots the time-series from multiple datasets for specified catchments, and also for specified time periods.