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Contents:



ozone from TOMSOzone from TOMS

 The dataset consists of 1° x 1° world gridded monthly averaged total column ozone. It is derived from the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) monthly averaged total column ozone data gridded at 1.25° x 1° longitude-latitude. The Nimbus-7 TOMS data is the only source of high resolution global information about the total ozone content of the atmosphere for the period November 1, 1978 - May 6, 1993 (McPeters et al., 1996). The ozone dataset was produced by the Ozone Processing Team (OPT) of the Atmospheric Chemistry and Dynamics Branch at the Goddard Space Flight Centre, using final Nimbus-7, Version 7, OPT data reduction algorithm, and was released in the Spring of 1996. This ozone dataset is important in studies involving atmospheric chemistry and upper air dynamics on both short (interannual) and long (decadal) time scales.

Documentation available on CD-ROM


The data is available on Volume 1 of the CIDC CD set.




greenhouse gases Greenhouse Gases from CDIAC

Precise records of past and present atmospheric carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) concentrations are critical to studies attempting to understand the effects these gases have on climate change. Researchers have attempted to determine past levels of the atmospheric gases by a variety of techniques, including direct measurements of trapped air in polar ice cores, indirect determinations from carbon isotopes in tree rings, analysis of spectroscopic data, and measurements of carbon and oxygen isotopic changes in carbon sediments in deep-ocean cores. The modern period of precise atmospheric measurements began during the International Geophysical Year (1958) with Keeling's (Scripps Institution of Oceanography) pioneering determinations at Mauna Loa, Hawaii and at the South Pole. Since that time the number of sites that measure atmospheric gases has grown to over sixty sites on both the land surface and ocean.

This dataset describes Atmospheric Chemistry records and isotope temperature records acquired from the Carbon Dioxide Information Analysis Center (CDIAC) Trends '93: A Compendium of Data on Global Change. Trends '93 is part of CDIAC continuing effort to distribute, in an accessible format, scientific data critical to global-change issues.

This subset of the Trends '93 collection includes the following:

Readers may note that two apparently different systems of units have been used in presenting the atmospheric data. For data from ice cores and for some modern atmospheric records, levels are presented as concentrations in parts per million by volume (ppmv). For much of the modern data, values are given as mixing ratios, in parts per million or in parts per million by volume. These differences in unit designations reflect the preferences of the researchers who have contributed their respective data sets for inclusion in Trends '93. In the context of atmospheric concentration in parts per million by volume refers to the number of volumes of the particular gas (CO2, CH4 and N2O) per million volumes of sample. In this same context, mixing ratio in parts per million is derived by dividing the number of moles of the particular gas (CO2, CH4 and N2O) by the total number of moles in the sample and then multiplying the quotient by one million. Assuming that the volume of a gas is proportional to the number of moles contained within the volume (this assumption should be valid for a gas (CO2, CH4 and N2O) in air under the conditions that atmospheric measurements are routinely carried out), we can expect that a gas (CO2, CH4 and N2O) concentrations should be equivalent to the same gases mixing ratios. For all practical applications, therefore, users of this data should consider the terms concentration and mixing ratio to be interchangeable.

Documentation available on CD-ROM


The data is available on Volume 1 of the CIDC CD set.