IDF Curve Analysis Tool

Visualize, analyze, and download rainfall intensity-duration-frequency data

Analysis Controls
Data Used in the IDF Curve Tool

The IDF Curve Tool in NIH-DHAARA is built using three major rainfall datasets: IMDAA reanalysis, ERA5 reanalysis, and future climate projections from the BCC-CSM2-MR model (bias-corrected CMIP6 data). These datasets together provide historical, high-resolution rainfall information and future climate scenarios, enabling robust hydrological design and climate-resilient planning.

1. IMDAA Reanalysis Dataset (2000–2022)

The Indian Monsoon Data Assimilation and Analysis (IMDAA) dataset is a high-resolution regional reanalysis developed by NCMRWF. It uses the Met Office Unified Model with 4D-Var assimilation to generate accurate rainfall fields for the Indian region.

  • Spatial resolution: ~0.12° (~12 km)
  • Temporal resolution: 1-hourly rainfall
  • Coverage: Indian subcontinent and surrounding areas
  • Period used in this tool: 2000–2022

IMDAA provides one of the most realistic reconstructions of Indian monsoon rainfall in the satellite era, making it suitable for short-duration extreme rainfall analysis and design applications.

Reference:

Rani, S.I., et al. (2021). IMDAA: High-resolution satellite-era reanalysis for the Indian monsoon region. Journal of Climate, 34(12), 5109–5133. DOI: 10.1175/JCLI-D-20-0412.1

Data Access:

https://rds.ncmrwf.gov.in/dashboard/download

2. ERA5 Reanalysis Dataset (2000–2022)

ERA5, produced by the Copernicus Climate Change Service, provides globally consistent hourly rainfall estimates. It is widely used for hydrological and climate assessments due to its long-term reliability and spatial uniformity.

  • Spatial resolution: ~0.25° (~25 km)
  • Temporal resolution: 1-hourly precipitation
  • Coverage: Global
  • Period used in this tool: 2000–2022

ERA5 serves as a reliable baseline dataset offering long-term climate consistency and global comparability.

Reference:

Hersbach, H., et al. (2023). ERA5 hourly data on single levels from 1940 to present. Copernicus Climate Data Store. DOI: 10.24381/cds.adbb2d47

Data Access:

https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels?tab=download

3. Future Climate Projections (Bias-Corrected CMIP6, 2015–2100)

To estimate IDF curves under climate change, the tool uses bias-corrected and downscaled projections from the BCC-CSM2-MR Global Climate Model (CMIP6). Raw GCM rainfall often contains systematic biases; therefore, bias correction significantly improves realism, particularly over South Asia.

  • Model used: BCC-CSM2-MR (Beijing Climate Center Climate System Model)
  • Data type: Bias-corrected rainfall projections (CMIP6)
  • Spatial resolution after bias correction: ~0.25° (~25 km)
  • Temporal coverage: 2015–2100
  • Region covered: South Asia including India

Climate Scenarios (SSPs):

The tool supports multiple Shared Socioeconomic Pathways (SSPs) representing different global emission and development trajectories:

  • SSP1-2.6 (Low Emissions): Sustainable pathway with reduced emissions
  • SSP2-4.5 (Medium Emissions): Middle-of-the-road scenario
  • SSP3-7.0 (High Emissions): High challenges to mitigation, regional rivalry
  • SSP5-8.5 (Very High Emissions): Fossil-fuel–driven growth with highest warming

These scenarios help users understand potential changes in extreme rainfall under different future climate conditions.

References:

Wu, T., et al. (2019). The Beijing Climate Center Climate System Model (BCC-CSM): Progress from CMIP5 to CMIP6. Geoscientific Model Development, 12, 1573–1600.

Mishra, V., Bhatia, U., Tiwari, A.D. (2020). Bias-corrected climate projections for South Asia from CMIP6. Scientific Data, 7, 338. DOI: 10.1038/s41597-020-00681-1

Dataset Summary
Dataset Type Spatial Resolution Temporal Resolution Years Used Purpose
IMDAA Regional reanalysis ~12 km 1-hourly 2000–2022 High-resolution Indian rainfall reconstruction
ERA5 Global reanalysis ~25 km 1-hourly 2000–2022 Long-term consistent rainfall dataset
BCC-CSM2-MR (Bias-Corrected CMIP6) Future climate projections ~25 km Daily 2015–2100 Future IDF curves under climate change
How to Use
  1. Select a dataset from the dropdown
  2. Enter coordinates or click on the map
  3. Click "Analyze Data" to generate results
  4. View charts and tables in the results panel
  5. Download data or generate reports

Select a location and click Analyze to view results

Data table will appear here