Abstract
Observational and modeling studies suggest that Earth's tropical belt has widened over the late 20th century and will continue to widen throughout the 21st century. Yet, estimates of tropical-width variations differ significantly across studies. This uncertainty, to an unknown degree, is partly due to the large variety of methods used in studies of the tropical width. Here, methods for eight commonly used metrics of the tropical width are implemented in the Tropical-width Diagnostics (TropD) code package in the MATLAB programming language. To consolidate the various methods, the operations used in each of the implemented methods are reduced to two basic calculations: finding the latitude of a zero crossing and finding the latitude of a maximum. A detailed description of the methods implemented in the code and of the code syntax is provided, followed by a method sensitivity analysis for each of the metrics. The analysis provides information on how to reduce the methodological component of the uncertainty associated with fundamental aspects of the calculations, such as monthly vs. seasonal averaging biases, grid dependence, sensitivity to noise, and sensitivity to threshold criteria.
| Original language | American English |
|---|---|
| Pages (from-to) | 4339-4357 |
| Number of pages | 19 |
| Journal | Geoscientific Model Development |
| Volume | 11 |
| Issue number | 10 |
| DOIs | |
| State | Published - 26 Oct 2018 |
Bibliographical note
Funding Information:This work is part of the collaborative efforts of the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project and the US Climate Variability and Predictability Program (US CLIVAR) Changing Width of the Tropical Belt Working Group. The authors thank the members of these groups as well as the ISSI and US CLIVAR offices and sponsoring agencies (ESA, Swiss Confederation, Swiss Academy of Sciences, University of Bern, NASA, NOAA, NSF, and DOE) for their support. We acknowledge the World Climate Research Programme's Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups for producing and making available their model output. Ori Adam acknowledges support by the Israeli Science Foundation grant 1185/17. Alison Ming acknowledges funding from the NERC standard grant code NE/N011813/1.
Funding Information:
Acknowledgements. This work is part of the collaborative efforts of the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project and the US Climate Variability and Predictability Program (US CLIVAR) Changing Width of the Tropical Belt Working Group. The authors thank the members of these groups as well as the ISSI and US CLIVAR offices and sponsoring agencies (ESA, Swiss Confederation, Swiss Academy of Sciences, University of Bern, NASA, NOAA, NSF, and DOE) for their support. We acknowledge the World Climate Research Programme’s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups for producing and making available their model output. Ori Adam acknowledges support by the Israeli Science Foundation grant 1185/17. Alison Ming acknowledges funding from the NERC standard grant code NE/N011813/1.
Publisher Copyright:
© 2018 Author(s).