The Cultural Committee of the Geography Department held its third seminar for the first semester of the current academic year 1437/1438 H on Wednesday 15 Rabi Awal, 1438 H, corresponding to 14 December 2016, headed by Dr. Omar bin Ali Al-Hazmi, and attended by the Department staff members, students and those who are interested in scientific activities at UQU level. The seminar was honored by the attendance of  Vice-Dean of the College of Social  Sciences for Academic Affairs, Dr. Khalid Bin Abdul Rahman Al-Ghamdi.

The Seminar entitled  "Some important applications of remote sensing technology" was presented by Dr. Abu Deif Farghaly, where the most important developments in the world of remote sensing were presented and discussed by the audience in a way that reflected the good scientific level of the Faculty staff members and staff of  the Systems and Remote Sensing Unit, who discussed extensively about satellite GRACE and its mechanism in gravity observation, gravimetric applications and its role in water management on planet earth.

Although water covers about 71% of the surface of the earth, around 2.5% of  Earth’s water is fresh, and more than two thirds of this amount is frozen water in glaciers and polar icebergs, which is water not available for use; hence fresh water actually became a limited resource, and demand has increased steadily over time, as the population growth is threatening to drain precious water resources, in addition to the decrease in the amount of fresh water with the spread of contamination, hence the need to ensure the safety and potability of water sources used by man of surface waters, rivers, lakes and groundwater or freezing water became a dire need.

In this respect, remote sensing entities and scientists are keen to study the availability of fresh water, evaluate its sources and control its types and their quality for submission to the decision maker, and to contribute to the management and preservation of freshwater through the launch of a group of satellites for this purpose.

It was possible to obtain many updated information through GRACE satellite and other means of modern remote sensing that contribute to water management, such as terrestrial water storage amounts such as quantities of snow piles, surface and deep soil moisture, groundwater  reserve and water lakes; assessing, modeling and predicting of water fluxes such as evaporation, respiration, precipitation and river flow. Also, applications of remote sensing for monitoring of water quality such as turbidity, dissolved oxygen and pollution.

GRACE data helps scientists monitor changes in water storage in large areas as mentioned earlier, this is done as follows: GRACE satellite records changes in gravity, which correspond to the changes in the mass, the mass change is due to water movement, so scientists isolate the part of the total change in mass caused by water movement in each region. Water sensing scientists combine information derived from GRACE with soil moisture information and evaporation, precipitation and other data (from other sensors) to isolate the estimated changes in underground water storage, while repeating this information monthly, GRACE satelite allows them to monthly monitor the change in the storage of water in groundwater reservoirs.

The results of the studies conducted using GRACE data on 37 world groundwater reservoirs including 4 reservoirs in the Middle East: the Arab Reservoir in KSA, number 22, Nubian reservoir in Egypt, number 1, North Africa reservoir, number 2 and a reservoir in Algeria, another in Mauritania and Senegal. The study showed that all groundwater reservoirs in the Arab world are suffering from lack of supply, while they suffer from a great deficiency and severe drain in their water reserve, as a result of increasingly severe withdraw and lack of storage in the reservoirs.