Dr. Husain Najafi

Early-Warning Systems Scientist

Service Manager, HS2S & FFS4DE

Department of Computational Hydrosystems (CHS)
Helmholtz Centre for Environmental Research (UFZ)
Permoserstraße 15 · 04318 Leipzig, Germany

Multi-hazard early warning systems · Impact-based forecasting
Research-to-operations · Capacity development

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Hydrological Forecasting and Impact-Based Early Warning

I develop and manage high-resolution flood and drought forecasting systems that turn hydrological predictions into impact-based early warning. My work spans the full chain — from hydro-meteorological forecasts and their evaluation to inundation, exposure, and impact — building reproducible, transferable workflows that move research into operations with forecasting agencies and international partners.

Featured Research

Selected first-author research advancing high-resolution flood and drought early warning.

Impact-based flood early warning

High-resolution simulation of flood inundation during the July 2021 Ahr flood. — Flood inundation during the July 2021 Ahr flood. Source: Najafi et al. (2024), Nature Communications, CC BY 4.0.

Awards & Recognition

2026 — Invited Speaker, MENAGFOST | Amman, Jordan

Presentation: Making Forecasts Actionable, Together: Flood and Drought Early Warning between Germany and MENA
Jointly hosted and funded by the Alexander von Humboldt Foundation and the Royal Scientific Society.

2022 — UFZ Young Scientist Award | Helmholtz Centre for Environmental Research, Germany

Recognized for contributions to application-oriented hydrological forecasting and the development of operational, high-resolution flood and drought early-warning systems in Germany.

2017 — International Affairs Scholarship | University of Tehran, Iran

Competitive award supporting doctoral research visits at Princeton University and Columbia University (International Research Institute for Climate and Society – IRI).

Forecasting Systems - HS2S and FFSDE

HS2S – Sub-seasonal Soil Moisture Forecast System (Experimental) Provides 1-km-resolution drought forecasting outlooks up to six weeks ahead, complementing the German Drought Monitor. Designed as an automated and transferable workflow.

HS2S — 1-km real-time drought outlooks (V2, 2021–now)

2-Week Streamflow Forecast Outlook

FFS4DE – Experimental flood forecasting for Germany
Developed and tested for 1,500+ CAMELS-DE catchments, linking meteorological forecasts, hydrological modelling, automated workflows, and impact-based layers to support flood early-warning research and research-to-operations learning.

Experimental Flood Forecasting System

Latest ECMWF Forecast for total weekly precipitation

Selected Projects

HI-CAM II — Helmholtz Climate Initiative (2023–2025) | Co-Principal Investigator

Development of high-resolution flash-flood forecasting, inundation modelling, and impact assessment workflows for Germany, connecting hydrological predictions with potential consequences for exposed populations and infrastructure.

International Collaboration & Capacity Development

Since 2020, I have served as the technical point of contact for ECMWF forecast products supporting HS2S and as the focal point for testing DWD–SINFONY products at the national scale. I am also a member of the Hydrological Ensemble Prediction Experiment (HEPEX).

Building on my experience in Germany, I am extending my research-to-operations (R2O) work through Europe–Africa and Europe–MENA scientific partnerships, focusing on co-developing open, transferable, and locally adaptable early warning workflows, strengthening technical and institutional capacities, and supporting long-term local ownership.

I welcome collaboration with national hydrometeorological services, research institutions, and regional organizations on flood and drought early warning, impact-based forecasting, and research-to-operations.

Supervision

M.Sc student — Salar Sarvari Nouri: Developing a glacier module for mHM (ongoing).
Postdoctoral researcher — Mehrdad Mohannazadeh (2023–25): radar- and observation-based product post-processing for hydrological modelling.

Selected Publications

High-resolution drought early warning for Germany
Najafi et al., 2026 – Environmental Research Letters High-resolution soil moisture forecasts for drought early warning in Germany. DOI 10.1088/1748-9326/aeb369

Impact-based riverine flood early warning

Najafi et al., 2024 – Nature Communications High-resolution impact-based early warning system for riverine flooding. https://doi.org/10.1038/s41467-024-48065-y

This paper has received substantial international attention, including more than 29,000 downloads, and a highlight by UNDRR PreventionWeb

Seasonal climate forecasting

Najafi, H., Robertson, A. W., Massah Bavani, A. R., Irannejad, P., Wanders, N., & Wood, E. F. (2021). Improved multi-model ensemble forecasts of Iran’s precipitation and temperature using a hybrid dynamical–statistical approach during fall and winter seasons. International Journal of Climatology, 41(12), 5698–5725. https://doi.org/10.1002/joc.7148

Hydro-meteorological extremes

Vorogushyn, S., Han, L., Apel, H., Nguyen, V. D., Guse, B., Guan, X., Rakovec, O., Najafi, H., Samaniego, L., & Merz, B. (2025). It could have been much worse: spatial counterfactuals of the July 2021 flood in the Ahr Valley, Germany. Natural Hazards and Earth System Sciences, 25(6), 2007–2029. https://doi.org/10.5194/nhess-25-2007-2025

Handwerker, J. H. et al. (2025). From initiation of convective storms to their impact — the Swabian MOSES 2023 campaign in southwestern Germany. Frontiers in Earth Science.

Santos, V. M., Casas-Prat, M., Poschlod, B., Ragno, E., Van Den Hurk, B., Hao, Z., Kalmár, T., Zhu, L., & Najafi, H. (2021). Statistical modelling and climate variability of compound surge and precipitation events in a managed water system: A case study in the Netherlands. Hydrology and Earth System Sciences, 25(6), 3595–3615. https://doi.org/10.5194/hess-25-3595-2021

Manuscripts under review

Mohannazadeh Bakhtiari, M., Modiri, E., Nguyen, V. D., Rakovec, O., Samaniego, L. E., and Najafi, H. Closing the latency gap for operational flood forecasting: near-real-time 1-km hourly gridded forcing in Germany. Hydrology and Earth System Sciences, under review.

Find more information on below links

LINKEDIN

ORCID iD

Google Scholar

Contact

Head
Prof. Dr. Sabine Attinger
Department of Computational Hydrosystems
tbl-modmon@ufz.de

Deputy Head
Prof. Dr. Luis Samaniego
Department of Computational Hydrosystems
luis.samaniego@ufz.de

Assistance
Nora Pabst
Phone +49 341 6025-2367

Sindy Bleiholder
Phone +49 341 6025-1250

Susanne Gangloff
Phone +49 341 6025-2533

sekces@ufz.de

Permoserstraße 15 | 04318 Leipzig

News / Press

Aug 2026

New research published in Nature Communications by Goyal et al., on "Quantifying environmental co-benefits of nitrogen-based crop restructuring and its implications on India’s interstate trade network". In its first predictive modelling kind of analysis, the study demonstrates how integrating nutrient management into crop-restructuring strategies can support food-system sustainability in India and other resource-constrained agricultural systems.

Aug 2025

New research published in Nature Food by Batool et al. (2025) analyses the effectiveness of EU nitrogen reduction targets. Under the “Farm to Fork” (F2F) strategy of the “Green Deal”, the EU Commission aims to reduce nutrient losses by 50% by 2030 by requiring EU countries to cut chemical fertiliser use by 20%. As shown in our work such a uniform reduction in fertilizer use would not be sufficient.

May 2024

New research published in Nature Communications by Hussian et al., (2024) emphasizes the game-changing potential of near-real-time and impact-based flood prediction. Their study demonstrates a 10-meter floodplain inundation hindcast of the 2021 European Summer Flood, showcasing a 17-hour lead time for better disaster preparedness. Impact-based early warnings can empower local authorities with crucial data on citizens at-risk for targeted emergency responses.

July 30, 2023

Hitze und Dürre - Interview with climate researcher Jakob Zscheischler
in Deutschlandfunk (only in German, 10:50 min) Link to interview

May 16, 2023

Start of ESA funded project 4DHydro

The overarching objective of 4DHydro is to foster collaborations between the Earth Observation (EO) water cycle community developing novel high-resolution EO data products, and the land surface and hydrological modelling community (LSM/HM) engaged in advancing hyperresolution modelling of the hydrological cycle at regional and continental scales. By involving several European institutions 4DHydro will assess and improve data sets of EO as well as synchronize EO products and LSM/HM models in order to improve predictions of the hydrological system. Overall, it will assist end-users and decisions-makers as well as the EU Destination Earth initiative. The project’s kick-off meeting will take place in Leipzig on 21st of June 2023.

Jan 30, 2023

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The following paper received the ASCE-EWRI 2023 Award for Best Case Study in the Journal of Hydrologic Engineering.

Mai, J. , B. A. Tolson, H. Shen, É. Gaborit, V. Fortin, N. Gasset, H. Awoye, T. A. Stadnyk, L. M. Fry, E. A. Bradley, F. Seglenieks, A. G. Temgoua, D. G. Princz, S. Gharari, A. Haghnegahdar, M. E. Elshamy, S. Razavi, M. Gauch, J. Lin, X. Ni, Y. Yuan, M. McLeod, N. B. Basu, R. Kumar, O. Rakovec, L. Samaniego, S. Attinger, N. K. Shrestha, P. Daggupati, T. Roy, S. Wi, T. Hunter, J. R. Craig, and A. Pietroniro (2021):
The Great Lakes Runoff Intercomparison Project Phase 3: Lake Erie (GRIP-E)
Journal of Hydrologic Engineering, 26(9), 05021020. Accepted Feb 16, 2021.

https://ascelibrary.org/doi/10.1061/%28ASCE%29HE.1943-5584.0002097

Dec 1, 2022

Award Poster Masooma Batool

Masooma Batool won the "Best student poster award" at the XXI International Nitrogen Workshop.
This conference, hosted by ETSIAAB, Universidad Politécnica de Madrid, brought together nearly 300 papers from authors from 40 countries in Madrid, Spain, October 24-28, 2022.
At the conference, Masooma and her colleagues presented long-term trends in soil nitrogen (N) surplus across Europe (1850-2019). Excess N provides information on the trends and spatial distribution of N surplus in soil systems across Europe, highlighting agricultural areas in Central Europe as nitrogen hotspots. These areas have undergone dramatic changes over the past 150 years. Importantly, we show that estimates of N surplus are subject to large uncertainties, requiring explicit consideration of these uncertainties when analyzing past trends in N surplus.

Nov 15, 2022

Earthrise - Mission Klima
How our research contributes to climate mitigation and adaptation is demonstrated in this WELT report.

Video at www.welt.de (only in German)

05:50': Hohes Holz research station
10:40': FORMIND in the Vislab
15:45': Fragmentation of forests
43:00': FORMIND and climate scenarios

Oct 12, 2022

Dr. Husain Najafi won the UFZ Young Scientist Award for Applied Research 2022. The award goes to him for his excellence and dedication in development of the operational drought forecasting system in Germany and investigation of 2021 summer flood predictability. Hydrological forecasting systems are the fundamental component of early warning systems - disaster risk reduction.

Older news are stored in the news archive.

New publications

Najafi, H., Shrestha, P.K., Rakovec, O. et al. High-resolution impact-based early warning system for riverine flooding. Nat Commun 15, 3726 (2024). https://doi.org/10.1038/s41467-024-48065-y
Henniger, H., Huth, A., Frank, K., & Bohn, F. J. (2023). Creating virtual forests around the globe and analysing their state space. Ecological Modelling, 483, 110404. https://doi.org/10.1016/j.ecolmodel.2023.110404

In this paper we present the "Forest Factory 2.0″ algorithm, which generates various virtual forest stands for different biomes on Earth. To demonstrate the potential of this approach, we analyse different forest-structure->ecosystem-function relationships across biomes.
Friedrich Boeing, Oldrich Rakovec, Rohini Kumar, Luis Samaniego, Martin Schrön, Anke Hildebrandt, Corinna Rebmann, Stephan Thober, Sebastian Müller, Steffen Zacharias, Heye Bogena, Katrin Schneider, Ralf Kiese, Sabine Attinger, and Andreas Marx. High-resolution drought simulations and comparison to soil moisture observations in Germany. Hydrol. Earth Syst. Sci., 26, 5137–5161, 2022. https://doi.org/10.5194/hess-26-5137-2022

In this paper, we deliver an evaluation of the second generation operational German drought monitor ( https://www.ufz.de/duerremonitor ) with a state-of-the-art compilation of observed soil moisture data from 40 locations and four different measurement methods in Germany. We show that the expressed stakeholder needs for higher resolution drought information at the one-kilometer scale can be met and that the agreement of simulated and observed soil moisture dynamics can be moderately improved.
Mahnken, M., Cailleret, M., Collalti, A., Trotta, C., Biondo, C., D’Andrea, E., ... & Reyer, C. P. O. (2022). Accuracy, realism and general applicability of European forest models. Global Change Biology. DOI: 10.1111/gcb.16384
Pacheco-Labrador, J., Weber, U., Ma, X., Mahecha, M. D., Carvalhais, N., Wirth, C., Huth, A., Bohn, F. J., Kraemer, G., Heiden, U., FunDivEUROPE members, and Migliavacca, M.: EVALUATING THE POTENTIAL OF DESIS TO INFER PLANT TAXONOMICAL AND FUNCTIONAL DIVERSITIES IN EUROPEAN FORESTS, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLVI-1/W1-2021, 49–55, 2022. DOI: 10.5194/isprs-archives-XLVI-1-W1-2021-49-2022
Bevacqua, E., De Michele, C., Manning, C., Couasnon, A., Ribeiro, A.F.S., Ramos, A.M., Vignotto, E., Bastos, A., Blesić, S., Durante, F., Hillier, J., Oliveira, S.C., Pinto, J.G., Ragno, E., Rivoire, P., Saunders, K., van der Wiel, K., Wu, W., Zhang, T., Zscheischler, J. (2021): Guidelines for Studying Diverse Types of Compound Weather and Climate Events. Earth Future. 10.1029/2021EF002340
Najafi H, Robertson AW, Massah Bavani AR, Irannejad P, Wanders N, Wood EF. Improved multi-model ensemble forecasts of Iran's precipitation and temperature using a hybrid dynamical-statistical approach during fall and winter seasons. Int
J Climatol. 2021;1–28. DOI: 10.1002/joc.7148

Hari, V., Rakovec, O., Markonis, Y. et al. Increased future occurrences of the exceptional 2018–2019 Central European drought under global warming. Sci Rep 10, 12207 (2020). DOI: 10.1038/s41598-020-68872-9

Schmidt, L., Heße, F., Attinger, S., Kumar, R., (2020): "Challenges in applying machine learning models for hydrological inference: A case study for flooding events across Germany", Water Resources Research DOI: 10.1029/2019WR025924

Jing, M., Kumar, R., Heße, F., Thober, S., Rakovec, O., Samaniego, L., Attinger, S., (2020): "Assessing the response of groundwater quantity and travel time distribution to 1.5, 2, and 3 °C global warming in a mesoscale central German basin", Hydrology and Earth System Sciences DOI: 10.5194/hess-24-1511-2020

Sep 2, 2022

The collaborative project "Standardisiertes Monitoring von Wachstumsreaktionen wichtiger Waldbaumarten auf klimatische Extremereignisse" (MW³) with participation of the UFZ will develop a standardized monitoring system and protocol to record growth responses of important Central European forest tree species with a focus on climatic extremes. Future extreme events and their impact on forest carbon fluxes in Germany will be analyzed using smart models.