The chemistry of precipitation for the island of Hawaii during the HAMEC Project.

Miller, John M.; Stensland, Gary J.; Semonin, Richard G.

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https://hdl.handle.net/2142/109956 Copy

Description

Title

The chemistry of precipitation for the island of Hawaii during the HAMEC Project.

Author(s)

• Miller, John M.
• Stensland, Gary J.
• Semonin, Richard G.

Issue Date

1984-11

Keyword(s)

• Hawaii Mesoscale Energy and Climate Project (HAMEC)
• Precipitation chemistry
• Acidity
• pH measurement

Geographic Coverage

Hawaii

Abstract

During the Hawaii Mesoscale Energy and Climate Project (HAMEC), a program of precipitation chemistry measurements was conducted using daily and sequential collection techniques. Determination of pH and conductivity were made on site for the daily samples, and all samples were shipped to the Illinois State Water Survey for analysis of major ions. During the period of study,June 11-24, 1980, over 300 sequential rain samples were collected at the Hilo site. The acidity of these samples was very similar to the 5-year acidity distribution of Hilo with a median pH of 4.7. Enrichment calculations showed that the chloride and magnesium levels were consistent with seawater ratios; potassium and calcium levels were 20%-40% greater and sulfate was more than 100% in excess of levels expected from seawater ratios. The daily samples collected at nine sites from Hilo (60 m) to Mauna Loa Observatory (3400 m) showed a steady decrease in seasalt constituents with elevation. The acidity also decreased with elevation, a condition that did not follow the increase with elevation measured over the previous 5-year sampling program. It was also found that nitrate decreased less rapidly with elevation than did excess sulfate. Implications of these HAMEC results are interpreted in terms of long-range transport. Differences in field and laboratory pH measurements are explained as an indication of unmeasured inorganic acids. At the time of the field pH measurements (within 24 hours of the rainfall) the organic acids were calculated to contribute hydrogen ion concentrations that were from 35% to 282% of the levels from strong mineral acids.

Publisher

National Oceanic and Atmospheric Administration (NOAA) Environmental Research Laboratories

Series/Report Name or Number

• NOAA Technical Memorandum ERL ARL no. 133
• ISWS Contract Report CR 361

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/109956

Sponsor(s)/Grant Number(s)

NOAA

Copyright and License Information

Public domain, federal government document.

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