Flood or Drought: How Do Aerosols Affect Precipitation?

• DOI: 10.1126/science.1160606
• Publication Date: 2008-09-07T16:13:59Z
• Authors: Daniel Rosenfeld; Ulrike Lohmann; Graciela B. Raga; Colin D. O'Dowd; Markku Kulmala; Sandro Fuzzi; Anni Reissell; Meinrat O. Andreae
• Keywords: Cloud condensation nuclei; Haze

Aerosols serve as cloud condensation nuclei (CCN) and thus have a substantial effect on properties the initiation of precipitation. Large concentrations human-made aerosols been reported to both decrease increase rainfall result their radiative CCN activities. At one extreme, pristine tropical clouds with low rain out too quickly mature into long-lived clouds. On other hand, heavily polluted evaporate much water before precipitation can occur, if they form at all given reduced surface heating resulting from aerosol haze layer. We propose conceptual model that explains this apparent dichotomy.