Tag Archives: rain

Computerized model showing simulation of the city of Jeddah under flooding conditions. The cloudy sky indicates the spatial distribution of the amount of rain over Jeddah. Credit: KAUST

KAUST scientists developing models to predict extreme events

As KAUST celebrates its five-year anniversary, the community has a plethora of milestones to celebrate, not to mention more than a few memorable events to look back on. Interestingly, one of these noteworthy events, in the form of an unforeseen natural occurrence, still serves as the basis for ongoing interdisciplinary research at the University. Shortly following KAUST’s Inauguration, on November 25, 2009, over 140 millimeters of rain fell over the Jeddah region within a mere eight hours, causing in excess of 100 fatalities and resulting in an economic setback of over $100M.

“All this rain coming at the same time, in a matter of few hours, meant the water had nowhere to go; so it went into the streets,” said KAUST’s Ibrahim Hoteit, Associate Professor of Earth Sciences and Engineering and Principal Investigator of the Earth Fluid Modeling and Prediction group. Flash floods present a particular challenge in arid areas with limited sewage systems.

Computerized model showing simulation of the city of Jeddah under flooding conditions. The cloudy sky indicates the spatial distribution of the amount of rain over Jeddah. Credit: KAUST
Computerized model showing simulation of the city of Jeddah under flooding conditions. The cloudy sky indicates the spatial distribution of the amount of rain over Jeddah. Credit: KAUST

“The rain doesn’t get quickly absorbed in this region.” As Prof. Hoteit further explains: “We’re trying to reconstruct the rain event that happened during the 2009 and 2001 floods using modeling and observations.” As he emphasizes, “models predict the future data and the data guide the model toward the truth.”

He points to an impressive computerized model of Jeddah on his monitor, capturing over 20,000 buildings, complete with surrounding mountains and estimated paths taken by the water as it flooded the city.

Constructing Predictive Models for Jeddah Flooding

“In order to build a local model at the level of Jeddah, we downscale from global to regional MENA (Middle East & North Africa)-wide models all the way down to a few hundred meters over Jeddah,” as Hoteit outlines. To obtain the MENA region data, his team used data from satellites and international sources.

As they eventually zoomed in over the Jeddah region, the local data was provided by Presidency of Meteorology and Environment (PME) and the Jeddah Municipal government. The data collected is then used to complement and guide the atmospheric and weather models employed to forecast.

“Using all available observations and state-of-the-art weather forecasting models, our simulations suggest that we could predict these devastating extreme rain events one or two days in advance. So we can greatly improve the prediction of these events and issue timely warnings,” said Prof. Hoteit.

The rain is then used as input in developing very high-resolution models to simulate street flooding in the city of Jeddah.

It’s important to keep in mind that environmental fluid models are not perfect, and as such their outputs can be modeled as random variabilities with some distributions. “The question of how good or certain our forecast is dependent on a complex mathematical and computational problem. We strive to compute the best possible representation of the distribution of the system state given the models and available data.”

These sophisticated models, taking into account input and modeling uncertainties, are achieved through highly multidisciplinary work involving various teams at KAUST. Prof. Hoteit closely collaborates with KAUST’s Prof. Omar Knio, a world expert in the field of uncertainty quantification. He also relies heavily on collaborations with the high performance computing and visualization teams. “Visualization is very important for us as a way to communicate our scientific concepts to people and users,” explained Hoteit.

Ocean Modeling and the Impact of Sea Currents

In an effort to build forecasting models meant to predict extreme marine and weather events, Prof. Hoteit and his group also rely on ocean and atmospheric observations. For any environmental model to be effective, it’s important to complement it with actual data collected from the whole region and locally.

Working with data sets collected from Saudi Aramco, from PME, as well as from satellite data, KAUST was able to develop a 14-year reanalysis (from the years 2000 to 2014) of atmospheric conditions over the Red Sea at a 10-kilometer resolution – one of the highest and most accurate of its kind in the region.

As they eventually zoomed in over the Jeddah region, the local data was provided by Presidency of Meteorology and Environment (PME) and the Jeddah Municipal government. The data collected is then used to complement and guide the atmospheric and weather models employed to forecast.

“Using all available observations and state-of-the-art weather forecasting models, our simulations suggest that we could predict these devastating extreme rain events one or two days in advance. So we can greatly improve the prediction of these events and issue timely warnings,” said Prof. Hoteit.

The rain is then used as input in developing very high-resolution models to simulate street flooding in the city of Jeddah.

It’s important to keep in mind that environmental fluid models are not perfect, and as such their outputs can be modeled as random variabilities with some distributions. “The question of how good or certain our forecast is dependent on a complex mathematical and computational problem. We strive to compute the best possible representation of the distribution of the system state given the models and available data.”

These sophisticated models, taking into account input and modeling uncertainties, are achieved through highly multidisciplinary work involving various teams at KAUST. Prof. Hoteit closely collaborates with KAUST’s Prof. Omar Knio, a world expert in the field of uncertainty quantification. He also relies heavily on collaborations with the high performance computing and visualization teams. “Visualization is very important for us as a way to communicate our scientific concepts to people and users,” explained Hoteit.

Ocean Modeling and the Impact of Sea Currents

In an effort to build forecasting models meant to predict extreme marine and weather events, Prof. Hoteit and his group also rely on ocean and atmospheric observations. For any environmental model to be effective, it’s important to complement it with actual data collected from the whole region and locally.

Working with data sets collected from Saudi Aramco, from PME, as well as from satellite data, KAUST was able to develop a 14-year reanalysis (from the years 2000 to 2014) of atmospheric conditions over the Red Sea at a 10-kilometer resolution – one of the highest and most accurate of its kind in the region.

Source: KAUST