Editorial Type:
Article
Article Type:
Research Article

Does Air Pollution Really Suppress Precipitation in Israel?

P. Alpert Department of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel

Search for other papers by P. Alpert in
Current site
Google Scholar
PubMed Close
,
N. Halfon Department of Geography, Haifa University, Haifa, Israel

Search for other papers by N. Halfon in
Current site
Google Scholar
PubMed Close
, and
Z. Levin Department of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel

Search for other papers by Z. Levin in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Apr 2008
DOI:
https://doi.org/10.1175/2007JAMC1803.1
Page(s):
933–943
Restricted access

Abstract

Trends in the orographic rainfall ratio R0 over Israel are reevaluated. It is shown that the rainfall has not changed significantly over most of the mountainous stations, with some significant increases over the central mountains. The overall evaluation of R0 for all potential station pairs, calculating the ratio of each mountain station separately over each coastal or seashore station, indicates that about 50% of all pairs show a positive trend in R0. The high spatial variability, especially over the mountains, allows for finding orographic rainfall ratio trends that are significant in both the positive and negative directions. The correct definition of R0 in the Israeli case requires the use of a seashore cluster of stations. If some of the seashore stations are replaced by inland stations, and in particular stations that are right over the region of maximum positive rainfall urban enhancement due to the thermal heat island or other urban effects, a seemingly decreasing “orographic ratio” is unavoidable. In such a case, urban dynamical positive effects on coastal rainfall can be erroneously interpreted as pollution suppression of orographic rainfall. When seashore stations are selected as required by a proper definition of the orographic ratio, increasing R0 is obtained over central Israel and an insignificant trend over the north is found. Furthermore, evaluation of the ratio of rainfall for the upwind in comparison with the downwind side of the Galilee Mountains exhibits an increasing trend, opposite to the recent findings of Givati and Rosenfeld. The rainfall analysis shows no evidence of any suppression of rainfall over the mountains due to pollution, and at least in Israel other factors besides aerosols are predominant in defining the trends in the orographic rainfall ratio.

Corresponding author address: Prof. Pinhas Alpert, Dept. of Geophysics and Planetary Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel. Email: pinhas@cyclone.tau.ac.il

Abstract

Trends in the orographic rainfall ratio R0 over Israel are reevaluated. It is shown that the rainfall has not changed significantly over most of the mountainous stations, with some significant increases over the central mountains. The overall evaluation of R0 for all potential station pairs, calculating the ratio of each mountain station separately over each coastal or seashore station, indicates that about 50% of all pairs show a positive trend in R0. The high spatial variability, especially over the mountains, allows for finding orographic rainfall ratio trends that are significant in both the positive and negative directions. The correct definition of R0 in the Israeli case requires the use of a seashore cluster of stations. If some of the seashore stations are replaced by inland stations, and in particular stations that are right over the region of maximum positive rainfall urban enhancement due to the thermal heat island or other urban effects, a seemingly decreasing “orographic ratio” is unavoidable. In such a case, urban dynamical positive effects on coastal rainfall can be erroneously interpreted as pollution suppression of orographic rainfall. When seashore stations are selected as required by a proper definition of the orographic ratio, increasing R0 is obtained over central Israel and an insignificant trend over the north is found. Furthermore, evaluation of the ratio of rainfall for the upwind in comparison with the downwind side of the Galilee Mountains exhibits an increasing trend, opposite to the recent findings of Givati and Rosenfeld. The rainfall analysis shows no evidence of any suppression of rainfall over the mountains due to pollution, and at least in Israel other factors besides aerosols are predominant in defining the trends in the orographic rainfall ratio.

Corresponding author address: Prof. Pinhas Alpert, Dept. of Geophysics and Planetary Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel. Email: pinhas@cyclone.tau.ac.il

Save
Cover Journal of Applied Meteorology and Climatology
Journal of Applied Meteorology and Climatology

  • Alpert, P., 1986: Mesoscale indexing of the distribution of orographic precipitation over high mountains. J. Climate Appl. Meteor., 25 , 532–545.

    • Search Google Scholar
    • Export Citation

  • Alpert, P., and H. Shafir, 1991: On the role of the wind vector interaction with high-resolution topography in orographic rainfall modeling. Quart. J. Roy. Meteor. Soc., 117 , 421–426.

    • Search Google Scholar
    • Export Citation

  • Alpert, P., H. Shafir, and W. R. Cotton, 1994: Prediction of meso-γ-scale orographic precipitation. Trends in Hydrology, J. Menon, Ed., Council of Scientific Research Integration, 403–441.

    • Search Google Scholar
    • Export Citation

  • Alpert, P., I. Osetinsky, B. Ziv, and H. Shafir, 2004: Semi-objective classification for daily synoptic systems: Application to the eastern Mediterranean climate change. Int. J. Climatol., 24 , 1001–1011.

    • Search Google Scholar
    • Export Citation

  • Andreae, M. O., D. Rosenfeld, P. Artaxo, A. A. Costa, G. P. Frank, K. M. Longo, and M. A. F. Silva-Dias, 2004: Smoking rain clouds over the Amazon. Science, 303 , 1337–1342.

    • Search Google Scholar
    • Export Citation

  • Ben-Gai, T., A. Bitan, A. Manes, P. Alpert, and S. Rubin, 1998: Spatial and temporal changes in annual rainfall frequency distribution patterns in Israel. Theor. Appl. Climatol., 61 , 177–190.

    • Search Google Scholar
    • Export Citation

  • Browning, K. A., 1980: Structure, mechanism and prediction of orographically enhance rain in Britain. Orographic Effects in Planetary Flows, R. Hide and P. W. White, Eds., GARP Publ. Series, No. 23, 85–114.

    • Search Google Scholar
    • Export Citation

  • Changnon Jr., S. A., 1980: More on the LaPorte anomaly: A review. Bull. Amer. Meteor. Soc., 61 , 702–717.

  • Changnon Jr., S. A., F. A. Huff, and R. G. Semonin, 1971: METROMEX: An investigation of inadvertent weather modification. Bull. Amer. Meteor. Soc., 52 , 958–968.

    • Search Google Scholar
    • Export Citation

  • Dabberdt, W., and Coauthors, 2000: Forecast issues in the urban zone: Report of the 10th Prospectus Development Team of the U.S. Weather Research Program. Bull. Amer. Meteor. Soc., 81 , 2047–2064.

    • Search Google Scholar
    • Export Citation

  • Givati, A., and D. Rosenfeld, 2004: Quantifying precipitation suppression due to air pollution. J. Appl. Meteor., 43 , 1038–1056.

  • Givati, A., and D. Rosenfeld, 2005: Separation between cloud-seeding and air-pollution effects. J. Appl. Meteor., 44 , 1298–1315.

  • Goldreich, Y., 2003: The Climate of Israel: Observations, Research, and Applications. Kluwer Academic, 270 pp.

  • Goldreich, Y., and A. Manes, 1979: Urban effects on precipitation patterns in the greater Tel-Aviv area. Arch. Meteor. Geophys. Biokl., 27B , 213–224.

    • Search Google Scholar
    • Export Citation

  • Goldreich, Y., A. Freundlich, and P. Alpert, 1997: Rainfall anomaly over the lee side of Mount Carmel (Israel) and the associated wind field. J. Appl. Meteor., 36 , 748–762.

    • Search Google Scholar
    • Export Citation

  • Gunn, R., and B. B. Phillips, 1957: An experimental investigation of the effect of air pollution on the initiation of rain. J. Meteor., 14 , 272–280.

    • Search Google Scholar
    • Export Citation

  • Hill, F. F., K. A. Browning, and M. J. Bader, 1981: Radar and rain gauge observations of orographic rain over south Wales. Quart. J. Roy. Meteor. Soc., 107 , 643–670.

    • Search Google Scholar
    • Export Citation

  • Huschke, R. E., and Ed., 1959: Glossary of Meteorology. Amer. Meteor. Soc., 638 pp.

  • Jirak, I. L., and W. R. Cotton, 2006: Effect of air pollution on precipitation along the front range of the Rocky Mountains. J. Appl. Meteor. Climatol., 45 , 236–245.

    • Search Google Scholar
    • Export Citation

  • Landsberg, H. H., 1981: The Urban Climate. Elsevier, 275 pp.

  • Levin, Z., A. Teller, E. Ganor, and Y. Yin, 2005: On the interactions of mineral dust, sea salt particles and clouds—A measurement and modeling study from the MEIDEX campaign. J. Geophys. Res., 110 .D20202, doi:10.1029/2005JD005810.

    • Search Google Scholar
    • Export Citation

  • Rosenfeld, J., J. Dai, X. Yu, Z. Yao, X. Xu, X. Yang, and C. Du, 2007: Inverse relations between amounts of air pollution and orographic precipitation. Science, 315 , 1396–1398.

    • Search Google Scholar
    • Export Citation

  • Shafir, H., and P. Alpert, 1991: On the urban orographic rainfall anomaly in Jerusalem—A numerical study. Atmos. Environ., 24B , 365–275.

    • Search Google Scholar
    • Export Citation

  • Steinberger, E. H., and N. Gazit-Yaari, 1996: Recent changes in spatial distribution on annual precipitation in Israel. J. Climate, 9 , 3328–3336.

    • Search Google Scholar
    • Export Citation

  • Tao, W-K., X. Li, A. Khain, T. Matsui, S. Lang, and J. Simpson, 2007: The role of atmospheric aerosol concentration on deep convective precipitation: Cloud-resolving model simulations. J. Geophys. Res., 112 .D24518, doi:10.1029/2007JD008728.

    • Search Google Scholar
    • Export Citation

  • Teller, A., and Z. Levin, 2006: The effects of aerosols on precipitation and dimensions of subtropical clouds; a sensitivity study using a numerical cloud model. Atmos. Chem. Phys., 6 , 67–80.

    • Search Google Scholar
    • Export Citation

  • van den Heever, S. C., and W. R. Cotton, 2007: Urban aerosol impacts on downwind convective storms. J. Appl. Meteor. Climatol., 46 , 828–850.

    • Search Google Scholar
    • Export Citation

  • van den Heever, S. C., G. G. Carrio, W. R. Cotton, P. J. DeMott, and A. J. Prenni, 2006: Impacts of nucleating aerosol on Florida convection. Part I: Mesoscale simulations. J. Atmos. Sci., 63 , 1752–1775.

    • Search Google Scholar
    • Export Citation

  • Warner, J., 1968: A reduction of rain associated with smoke from sugar-cane fires—An inadvertent weather modification. J. Appl. Meteor., 7 , 247–251.

    • Search Google Scholar
    • Export Citation

  • Warner, J., 1971: Smoke from sugar-cane fires and rainfall. Proc. Int. Conf. on Weather Modification, Canberra, ACT, Australia, Amer. Meteor. Soc., 191–192.

  • Yin, Y., Z. Levin, T. G. Reisin, and S. Tzivion, 2000: The effects of giant condensation nuclei on the development of precipitation in convective clouds—A numerical study. Atmos. Res., 53 , 91–116.

    • Search Google Scholar
    • Export Citation

  • Yosef, Y., 2007: Rainfall quantity and distribution trends in Israel as a function of daily rainfall 1950/1–2003/4 (in Hebrew). M.S. thesis, Dept. of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel, 70 pp.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 543 172 8
PDF Downloads 283 47 7