The proposed ‘Smart Watering System’ will consist of 3 Stages (as a processing workflow shown in Figure 1) divided into 10 steps. The 3 Stages are defined as follows: (i) Input (Steps 1-3) (ii) Reading / Processing (Steps 4-7) and (iii) Output (Steps 8-10). The overall methodology consists of the following 10 steps:

1) development of a web-based platform where the end-users will login entering some useful inputs such as contact details and information related to their fields;

2) cross-check of input data;

3) unique ID-code for each end-user will be created referring to each ‘spot’ & crop-type;

4) automatically processing of Sentinel data (satellite /radar) to extract useful crop-parameters and transfer derived information to the ‘Reading/Processing Database’;

5) linked each ‘spot’ of interest to the closer available meteorological station and transfer the corresponding meteorological data to the ‘Reading/Processing Database’;

6) field measurements acquired at the same time with Sentinel overpasses (spectroradiometric, LAI, crop-height etc) which will be used for validation purposes and test of the predictive algorithm;

7) processing the readings of steps 4-6 using the FAO56 equation to estimate the water demand for irrigation;

8) development of a mobile-app aiming to inform each end-user for the daily irrigation demand of their fields. Each end-user will receive automatically a notification through the ‘CropWATER’ mobile-app referring to the water quantity requirements on a daily-basis;

9) development of the Smart ‘CropWATER’ Valve. Loaded with several sensors it will be able to read inputs data from the sms card, measure and release automatically the needed water quantity to ensure that the water demand calculated from the previous stages will finally ends up to the fields without any human intervention;

10) validation of the results / product.

The methodology will be applied for selected crop types. The Penman-Monteith algorithm will be applied individually for each crop employing the necessary crop parameters using Sentinel data. The input parameters will differ according to the crop type for example leaf area index (LAI), crop height (CH), albedo (crop parameters) takes various values. Since Sentinel images will be acquired every week the development stages of the crops will be immediately identified. For the implementation of this study, selected farmers will collaborate with Agricultural Research Institute (ARI) and all the necessary parameters such as the crop-type, planting day, phenological stage and crop area will be given.

List of input parameters:

Monteith (Monteith and Unsworth, 1990), is a function of climate data such as temperature (T), humidity (RH%), solar radiation (Rs) and wind speed (U) and crop parameters, such as the surface albedo (a), the leaf area index (LAI) and the crop height (CH) which can be used to predict ETc:

ETc = f ( a, LAI ,CH, T, RH%, Rs, U )

Penman-Monteith adapted to satellite data algorithm:

Penman-Monteith method adapted to satellite data will be used to estimate ETc in mm/day. The specific equation needs both meteorological and remotely sensed data to be applied. The ETc  is  estimated  using  remote  sensing  after  CH  and  LAI  maps  are  created  to  specify  these  parameters  spatially  through Vegetation  Indices. The algorithm provides at the end of the procedure, direct values of daily ETc through maps of evapotranspiration.