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MSWX Dataset Guide

Overview

MSWX (Multi-Source Weather) is a global, daily, 0.1° meteorological dataset based on ERA5 reanalysis data, bias-corrected and validated against in-situ station observations. It provides consistent, high-quality weather data for climate and hydrological applications worldwide.

Data Access & Licensing

License: CC BY-NC 4.0 (Non-Commercial Use Only)

MSWX is released under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.

✅ Permitted Uses

  • Academic research at universities and research institutions
  • Non-profit scientific studies
  • Personal projects and non-commercial analysis
  • Government and NGO applications for public benefit
  • Educational purposes and teaching

❌ Prohibited Uses

  • Commercial products or services using MSWX data
  • For-profit companies incorporating MSWX into commercial offerings
  • Commercial consulting services based on MSWX data
  • Any revenue-generating use without explicit permission

How to Request Access

  1. Visit the MSWX website: https://www.gloh2o.org/mswx/
  2. Submit a data request describing your intended use
  3. Confirm non-commercial use in your application
  4. Receive approval and download instructions from the MSWX team
  5. Configure climdata with your Google Service Account credentials (see below)

⚠️ Compliance: By using MSWX via climdata, you agree to the CC BY-NC 4.0 license terms. Violations may result in legal action.

Google Drive API Setup

MSWX data is hosted on Google Drive and accessed through the Google Drive API using a Service Account. This ensures secure, traceable access without sharing passwords.

Step 1: Create a Google Cloud Project

  1. Go to Google Cloud Console
  2. Click "Select Project" → "New Project"
  3. Enter a project name (e.g., climdata-mswx)
  4. Click "Create"

Step 2: Enable Google Drive API

  1. In the left sidebar, go to APIs & Services → Library
  2. Search for "Google Drive API"
  3. Click on it and click "Enable"

Step 3: Create a Service Account

  1. Go to IAM & Admin → Service Accounts
  2. Click "Create Service Account"
  3. Enter a name (e.g., climdata-mswx-sa)
  4. Click "Create and Continue"
  5. Click "Done" (you can skip role assignments for read-only Drive access)

Step 4: Generate and Download JSON Key

  1. Click on the Service Account email you just created
  2. Go to the "Keys" tab
  3. Click "Add Key" → "Create new key"
  4. Select "JSON" and click "Create"
  5. A JSON file will download automatically — store it securely!

Step 5: Store the Key Securely

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# Create a hidden directory for credentials
mkdir -p ~/.climdata_conf

# Move the downloaded JSON file
mv ~/Downloads/service-account-key.json ~/.climdata_conf/service.json

# Restrict file permissions (Linux/macOS)
chmod 600 ~/.climdata_conf/service.json

# Add to .gitignore to prevent accidental version control commits
echo "~/.climdata_conf/" >> .gitignore

Step 6: Configure climdata

Update your climdata configuration to point to your service account JSON:

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from climdata import ClimData

overrides = [
    "dataset=mswx",
    "lat=52.5",
    "lon=13.4",
    "time_range.start_date=2010-01-01",
    "time_range.end_date=2020-12-31",
    "variables=[tasmin,tasmax,pr]",
    "data_dir=./data",
    "dsinfo.mswx.params.google_service_account=~/.climdata_conf/service.json",
]

extractor = ClimData(overrides=overrides)
ds = extractor.extract()

Available Variables

Variable Description Units Long Name
tasmin Daily minimum air temperature °C Minimum Temperature
tasmax Daily maximum air temperature °C Maximum Temperature
tas Daily mean air temperature °C Mean Temperature
pr Daily precipitation mm/day Precipitation
rsds Downward shortwave radiation W/m² Solar Radiation
hurs Relative humidity % Relative Humidity
sfcWind Wind speed m/s Surface Wind Speed

Spatial and Temporal Coverage

  • Spatial Resolution: 0.1° × 0.1° (approximately 10 km at equator)
  • Temporal Resolution: Daily
  • Global Coverage: Worldwide
  • Time Period: 1979–present (continuously updated)

Data Quality & Methodology

MSWX combines ERA5 reanalysis with bias correction using in-situ observations:

  1. ERA5 as baseline: High-resolution atmospheric reanalysis
  2. Station bias correction: Adjusted using quality-controlled weather station data
  3. Validation: Cross-validated against independent observations
  4. Uncertainty estimates: Available for selected variables

For detailed methodology, see the MSWX publications on https://www.gloh2o.org/mswx/

Usage Examples

Point Extraction

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from climdata import ClimData
from climdata.datasets.MSWX import MSWXmirror

overrides = [
    "dataset=mswx",
    "lat=52.5",  # Berlin
    "lon=13.4",
    "time_range.start_date=2020-01-01",
    "time_range.end_date=2020-12-31",
    "variables=[tasmin,tasmax,pr]",
    "data_dir=./data",
    "dsinfo.mswx.params.google_service_account=~/.climdata_conf/service.json",
]

extractor = ClimData(overrides=overrides)
mswx = MSWXmirror(extractor.cfg)
mswx.extract(point=(extractor.cfg.lon, extractor.cfg.lat))

ds = mswx.load(variable="tasmax")
print(ds)

Bounding Box Extraction

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# Extract a region (Germany)
mswx.extract(box={
    "lon_min": 5.8,
    "lon_max": 15.0,
    "lat_min": 47.3,
    "lat_max": 55.1
})

ds = mswx.load(variable="pr")
print(ds)  # Returns spatiotemporal data for the region

Workflow with Climate Indices

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overrides_wf = [
    "dataset=mswx",
    "lat=52.5",
    "lon=13.4",
    "time_range.start_date=2010-01-01",
    "time_range.end_date=2020-12-31",
    "variables=[tasmin,tasmax,pr]",
    "data_dir=./data",
    "dsinfo.mswx.params.google_service_account=~/.climdata_conf/service.json",
    "index=tn10p",      # Cold nights index
    "impute=BRITS",     # Optional: gap-filling
]

extractor = ClimData(overrides=overrides_wf)
result = extractor.run_workflow(actions=["extract", "impute", "calc_index", "to_nc"])
print(result)

Common Issues

Error: "No authentication provided" or "Google Drive API error"

Solution: Ensure: 1. Service account JSON key exists at the specified path 2. File path is correctly spelled in the config 3. Service account email has been shared with MSWX Google Drive folders

Error: "Service Account not authorized to access folder"

Solution: 1. Check your MSWX data request approval status 2. Confirm the service account email was shared with the correct folder 3. Contact MSWX support if access was granted but still failing

Downloads are slow

Solution: 1. Use time_range to limit data to only what you need 2. Consider requesting multiple points instead of a large bounding box 3. MSWX files are large; parallel downloads may be rate-limited by Google Drive

Data Citation

When publishing results using MSWX data accessed via climdata, cite:

  1. MSWX Dataset: Include the MSWX publication and DOI from https://www.gloh2o.org/mswx/
  2. climdata Package: Include version and GitHub repository
  3. License Compliance: State "Data used under CC BY-NC 4.0 license"

Example:

We used Multi-Source Weather (MSWX) data [citation] accessed via the climdata package [version X.X.X] under the CC BY-NC 4.0 license. Data were extracted for [location] during [time period].

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