DINCAE

DINCAE (Data-Interpolating Convolutional Auto-Encoder) is a neural network to reconstruct missing data in satellite observations which is described in the following open access paper: https://doi.org/10.5194/gmd-13-1609-2020

Installation

Python 3.6 or 3.7 with the modules:

• numpy (https://docs.scipy.org/doc/numpy/user/install.html)
• netCDF4 (https://unidata.github.io/netcdf4-python/netCDF4/index.html)
• TensorFlow 1.15 with GPU support (https://www.tensorflow.org/install)

Tested versions:

• Python 3.6.8
• netcdf4 1.4.2
• numpy 1.15.4
• Tensorflow version 1.15 (DINCAE does not work with TensforFlow 2.0; TensorFlow 1.5 does not work on python 3.8)

You can install those packages either with pip3 or with conda.

Documentation

The document is available at https://gher-ulg.github.io/DINCAE/.

Input format

The input data should be in netCDF with the variables:

• lon: longitude (degrees East)
• lat: latitude (degrees North)
• time: time (days since 1900-01-01 00:00:00)
• mask: boolean mask where true means the data location is valid
• SST (or any other varbiable name): the data

This is the example output from ncdump -h:

netcdf avhrr_sub_add_clouds {
dimensions:
	time = UNLIMITED ; // (5266 currently)
	lat = 112 ;
	lon = 112 ;
variables:
	double lon(lon) ;
	double lat(lat) ;
	double time(time) ;
		time:units = "days since 1900-01-01 00:00:00" ;
	int mask(lat, lon) ;
	float SST(time, lat, lon) ;
		SST:_FillValue = -9999.f ;
}

An example for how to create this file in the examples folder:

• python example
• julia example

Running DINCAE

Copy the template file run_DINCAE.py and adapt the filename, variable name and the output directory and possibly optional arguments for the reconstruction method as mentioned in the documentation. The code can be run as follows:

python3 run_DINCAE.py

Reducing GPU memory

Convolutional layers can require "a lot" of GPU memory. These parameters can affect GPU memory utilisation:

• reduce the mini-batch size
• use fewer layers (e.g. enc_nfilter_internal = [16,24,36] or [16,24])
• use less filters (reduce the values of the optional parameter enc_nfilter_internal)
• reduce frac_dense_layer, a parameter controlling the width of the dense layer in the bottleneck
• use a smaller domain or lower resolution

Example results

Link to animation

More information about this result is given in the linked paper.