Multi‐layer perceptron neural network based algorithm for estimating precipitable water vapour from MODIS NIR data

This Letter presents a multi-layer perceptron neural network (MLP-NN) based algorithm to quantitatively determine precipitable water vapour (PWV) directly from near infrared (NIR) radiance measured by the Moderate Resolution Imaging Spectroradiometer (MODIS). First, the background of the MLP-NN based algorithm is discussed briefly. Then, the radiance of MODIS NIR channels simulated through a radiative transfer model with a set of input variables covering a broad range of surface reflectance and water vapour content are used to train MLP-NN. Finally, PWV values derived by the MLP-NN based algorithm are compared with radiosonde observations and a root mean squared error of 5.2 kg m -2 is found from this comparison.