Ward et al. (2021) Synoptic timescale linkage between midlatitude winter troughs Sahara temperature patterns and northern Congo rainfall: A building block of regional climate variability

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: International Journal of Climatology
• Year: 2021
• Authors: M. Neil Ward, Andreas H. Fink, Richard J. Keane, Françoise Guichard, John H. Marsham, Douglas J. Parker, Christopher M. Taylor
• DOI: 10.1002/joc.7011

Research Groups

Not explicitly stated in the abstract.

Short Summary

This study identifies and characterizes a coherent synoptic sequence during November–March where upper-level midlatitude troughs over Iberia or the Central Mediterranean induce near-surface warming across the Sahara, which subsequently leads to statistically predictable rainfall events over Northern Congo (NC).

Objective

• To identify and characterize the lagged synoptic teleconnection pathways by which upper-level midlatitude troughs (Iberia/CMed) influence near-surface warming over the Sahara and trigger rainfall events over Northern Congo (NC).

Study Configuration

• Spatial Scale: North Africa, extending from midlatitudes (Iberia/Central Mediterranean) to equatorial latitudes (Northern Congo), Southwestern Asia, Eastern Africa, and the Western Indian Ocean.
• Temporal Scale: Synoptic sequence analysis focused on the November–March season; lag times of several days (e.g., 2–3 days for Central Mediterranean linkage).

Methodology and Data

• Models used: Composite sequence analysis; Statistical prediction models (for daily rainfall).
• Data sources: Daily atmospheric data (for trough strength indices, wind, moisture, and rainfall composites); Reanalysis or observational data (implied).

Main Results

• Midlatitude troughs over the Central Mediterranean (CMed) link to Northern Congo (NC) rainfall faster (2–3 days lag) than those originating over Iberia.
• Ahead of NC rainfall events, initial warming over the central Sahara migrates southeastward toward NC, reaching a typical magnitude of $1\text{ to }2 \text{ degrees Celsius}$ at $10\text{ to }15\text{ degrees North}$.
• These warming anomalies are statistically predictive of NC daily rainfall and associated atmospheric features, including anomalous low-level southerly wind, increased moisture, and vertical easterly shear extending up to $600 \text{ hPa}$.
• A secondary pathway for Iberia troughs involves direct atmospheric teleconnection leading to convection west of NC, which subsequently migrates eastward into NC.
• The lagged synoptic influence of these troughs is widespread, affecting much of North Africa, Southwestern Asia, Eastern Africa, and the Western Indian Ocean over several days.

Contributions

• Provides a novel, coherent synoptic framework linking specific midlatitude trough movements to equatorial rainfall predictability in North Africa.
• Offers practical value for weather forecasters by improving situational awareness across the influenced zones (equatorial to midlatitude).
• Establishes a framework for future climate timescale analyses of these teleconnections.

Funding

Not specified in the abstract.

Citation

@article{Ward2021Synoptic,
  author = {Ward, M. Neil and Fink, Andreas H. and Keane, Richard J. and Guichard, Françoise and Marsham, John H. and Parker, Douglas J. and Taylor, Christopher M.},
  title = {Synoptic timescale linkage between midlatitude winter troughs Sahara temperature patterns and northern Congo rainfall: A building block of regional climate variability},
  journal = {International Journal of Climatology},
  year = {2021},
  doi = {10.1002/joc.7011},
  url = {https://doi.org/10.1002/joc.7011}
}

Generated by BiblioAssistant using gemini-flash-latest (Google API)