Using Limited Time Periods as a Means to Evaluate Microwave Sounding Unit Derived Tropospheric Temperature Trend Methods

Persistent Link:
http://hdl.handle.net/10150/194417
Title:
Using Limited Time Periods as a Means to Evaluate Microwave Sounding Unit Derived Tropospheric Temperature Trend Methods
Author:
Randall, Robb M
Issue Date:
2007
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Limited Time Period (LTP) running trends are used to evaluate Microwave Sounding Unit (MSU) derived tropospheric temperature trend methods in an attempt to alleviate documented considerable disagreements between tropospheric datasets so investigation into the atmospheric variability is able to move forward.Regression derived coefficients were used to combine lower stratosphere (LS) and mid-troposphere to lower stratosphere (MT) simulated MSU channels from RATPAC radiosonde data. This protocol is used to estimate tropospheric temperature trends and compared to actual RATPAC derived tropospheric temperature trends. It is found that the statistical LS/MT combination results in greater than 50% error over some LTP. These errors are found to exist when strong cooling in the stratosphere is coincident with periods when the level separating cooling from warming is above the tropopause.LTP trends are also created from various MSU difference time series between the University of Alabama in Huntsville (UAH) and Remote Sensing System (RSS) group's lower troposphere (LT) and MT channels. Results suggest the greatest discrepancies over time periods where NOAA-11 through NOAA-15 adjustments was applied to the raw LT data over land. Discrepancies are shown to be dominated by differences in diurnal correction methods due to orbital drift. Comparison of MSU data with radiosonde data indicate that RSS's method of determining diurnal effects is overestimating the correction in the LT channel. Diurnal correction signatures still exist in the RSS LT time series and are likely affecting the long term trend with a warm bias.These findings suggest atmospheric amplification is not happening in the atmosphere using globally averaged data over the MSU era. There is evidence however from the radiosonde data that shows greater warming in the ~300-500 hPa layer than at the surface during some LTP in the complete radiosonde database. This temporal change in temperature trends warrants further studies on this subject.This research suggests overall that the temporal changes in temperature trend profiles and their causes are extremely important in our understanding of atmospheric changes and are themselves, not well characterized.
Type:
text; Electronic Dissertation
Keywords:
Atmospheric Sciences
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Atmospheric Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Herman, Benjamin M
Committee Chair:
Herman, Benjamin M

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleUsing Limited Time Periods as a Means to Evaluate Microwave Sounding Unit Derived Tropospheric Temperature Trend Methodsen_US
dc.creatorRandall, Robb Men_US
dc.contributor.authorRandall, Robb Men_US
dc.date.issued2007en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractLimited Time Period (LTP) running trends are used to evaluate Microwave Sounding Unit (MSU) derived tropospheric temperature trend methods in an attempt to alleviate documented considerable disagreements between tropospheric datasets so investigation into the atmospheric variability is able to move forward.Regression derived coefficients were used to combine lower stratosphere (LS) and mid-troposphere to lower stratosphere (MT) simulated MSU channels from RATPAC radiosonde data. This protocol is used to estimate tropospheric temperature trends and compared to actual RATPAC derived tropospheric temperature trends. It is found that the statistical LS/MT combination results in greater than 50% error over some LTP. These errors are found to exist when strong cooling in the stratosphere is coincident with periods when the level separating cooling from warming is above the tropopause.LTP trends are also created from various MSU difference time series between the University of Alabama in Huntsville (UAH) and Remote Sensing System (RSS) group's lower troposphere (LT) and MT channels. Results suggest the greatest discrepancies over time periods where NOAA-11 through NOAA-15 adjustments was applied to the raw LT data over land. Discrepancies are shown to be dominated by differences in diurnal correction methods due to orbital drift. Comparison of MSU data with radiosonde data indicate that RSS's method of determining diurnal effects is overestimating the correction in the LT channel. Diurnal correction signatures still exist in the RSS LT time series and are likely affecting the long term trend with a warm bias.These findings suggest atmospheric amplification is not happening in the atmosphere using globally averaged data over the MSU era. There is evidence however from the radiosonde data that shows greater warming in the ~300-500 hPa layer than at the surface during some LTP in the complete radiosonde database. This temporal change in temperature trends warrants further studies on this subject.This research suggests overall that the temporal changes in temperature trend profiles and their causes are extremely important in our understanding of atmospheric changes and are themselves, not well characterized.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAtmospheric Sciencesen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineAtmospheric Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHerman, Benjamin Men_US
dc.contributor.chairHerman, Benjamin Men_US
dc.contributor.committeememberBetterton, Eric A.en_US
dc.contributor.committeememberThome, Kurtis J.en_US
dc.contributor.committeememberYool, Stephen R.en_US
dc.contributor.committeememberZeng, Xubinen_US
dc.identifier.proquest2284en_US
dc.identifier.oclc659748134en_US
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