Keyhan Gavahi

Mr. Keyhan Gavahi

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 March 2022 in Science of The Total Environment
Verified
Journal Article
Closed access
KGKeyhan Gavahi
Keyhan Gavahi
PAPeyman Abbaszadeh
Peyman Abbaszadeh
Hamid MoradkhaniHamid Moradkhani
Hamid Moradkhani

1 December 2024 in Expert Systems with Applications
Verified
Journal Article
Closed access
ASAli Sattari
Ali Sattari
Ehsan ForoumandiEhsan Foroumandi
Ehsan Foroumandi
KGKeyhan Gavahi
Keyhan Gavahi
HMHamid Moradkhani
Hamid Moradkhani

7 May 2024 in Water Resources Research
Verified
Journal Article
Open access
Ehsan ForoumandiEhsan Foroumandi
Ehsan Foroumandi
KGKeyhan Gavahi
Keyhan Gavahi
Hamid MoradkhaniHamid Moradkhani
Hamid Moradkhani
Droughts are among the most devastating natural hazards, occurring in all regions with different climate conditions. The impacts of droughts result in significant damages annually around the world. While drought is generally described as a slow‐developing hazardous event, a rapidly developing type of drought, the so‐called flash drought has been revealed by recent studies. The rapid onset and strong intensity of flash droughts require accurate real‐time monitoring. Addressing this issue, a Generative Adversarial Network (GAN) is developed in this study to monitor flash droughts over the Contiguous United States (CONUS). GAN contains two models: (a) discriminator and (b) generator. The developed architecture in this study employs a Markovian discriminator, which emphasizes the spatial dependencies, with a modified U‐Net generator, tuned for optimal performance. To determine the best loss function for the generator, four different networks are developed with different loss functions, including Mean Absolute Error (MAE), adversarial loss, a combination of adversarial loss with Mean Square Error (MSE), and a combination of adversarial loss with MAE. Utilizing daily datasets collected from NLDAS‐2 and Standardized Soil Moisture Index (SSI) maps, the network is trained for real‐time daily SSI monitoring. Comparative assessments reveal the proposed GAN's superior ability to replicate SSI values over U‐Net and Naïve models. Evaluation metrics further underscore that the developed GAN successfully identifies both fine‐ and coarse‐scale spatial drought patterns and abrupt changes in the SSI temporal patterns that is important for flash drought identification.

23 July 2024 in Environmental Research Letters
Verified
Journal Article
Open access
PMPouya Moghaddasi
Pouya Moghaddasi
KGKeyhan Gavahi
Keyhan Gavahi
HMHamed Moftakhari
Hamed Moftakhari
Hamid MoradkhaniHamid Moradkhani
Hamid Moradkhani
Drought, a potent natural climatic phenomenon, significantly challenges hydropower systems, bearing adverse consequences for economies, societies, and the environment. This study delves into the profound impact of drought on hydropower generation (HG) in the United States, revealing a robust correlation between hydrologic drought and hydroelectricity generation. Our analysis of the period from 2003 to 2020 for the Contiguous United States (CONUS) indicates that drought events led to a considerable decline in hydroelectricity generation, amounting to approximately 300 million MWh, and resulting in an estimated loss of $28 billion to the sector. Moreover, our findings highlight the adverse environmental effect of drought-induced HG reductions, which are often compensated by increased reliance on natural gas usage, which led to substantial emissions of carbon dioxide (CO2), sulfur dioxide (SO2), and nitrogen oxide (NO X ), totaling 161 700 kilotons, 1199 tons, and 181 977 tons, respectively. In addition to these findings, we assess the state-level vulnerability of hydropower to drought, identifying Washington and California as the most vulnerable states, while Nevada exhibits the least vulnerability. Overall, this study enhances understanding of the multifaceted effects of drought on hydropower, which can assist in informing policies and practices related to drought management and energy production.

7 December 2025 in Advances in Water Resources
Verified
Journal Article
Open access
FAFatemeh Rezaei Aderyani
Fatemeh Rezaei Aderyani
KGKeyhan Gavahi
Keyhan Gavahi
Hamid MoradkhaniHamid Moradkhani
Hamid Moradkhani