|Institutions||Jet Propulsion Laboratory|
|Alma mater||Scripps Institution of Oceanography|
|Thesis||Combining satellite and in situ data to make improved estimates of upper-ocean thermal variability on eddy to global scales (2004)|
|Doctoral advisor||Dean Roemmich|
|Known for||Argo (oceanography)|
|Notable awards||Charles K. Witham Environmental Stewardship Award, JPL,  2011 Ocean Sciences Early Career Award from the American Geophysical Union|
Joshua "Josh" K. Willis is an oceanographer at NASA's Jet Propulsion Laboratory. His area of expertise is current sea level rise, as well as measuring ocean temperatures, and he helped develop the Argo system of XBTs. When sea level fell from 2010 to 2011, Willis stated that this was due to an unusually large La Niña transferring more rainfall over land rather than over the ocean as usually happens. In addition, Willis is the project scientist for Jason-3.
In 2006, Willis et al. published a time series measuring ocean heat content, which concluded that the ocean had cooled from 2003 to 2005. A similar conclusion was reached by scientists at NASA's Langley Research Center (LRC). While Willis cautioned against drawing conclusions based on such a short time period, the study was widely covered in the media, with climate change skeptics citing it as evidence that global warming was no longer occurring. Willis also noted that some model simulations show periods of four to five years during which the upper ocean does not warm. Willis suspected something was awry when the researchers at LRC concluded that Earth's energy imbalance had remained the same over that period of time, which led to a researcher at LRC named Takmeng Wong becoming "surprised, even a little alarmed" at Willis's results. The original 2006 paper has since been corrected, with Willis et al. stating, "Most of the rapid decrease in globally integrated upper (0–750 m) ocean heat content anomalies (OHCA) between 2003 and 2005 reported by Lyman et al.  appears to be an artifact resulting from the combination of two different instrument biases recently discovered in the in situ profile data."
On May 21, 2013, Willis co-authored a paper regarding measurements of ocean temperatures taken during the Challenger expedition in the 1870s, which were compared with measurements from Argo. This paper concluded that the global ocean had indeed warmed since the 1870s, and received wide media attention.
- Willis, J. K. (2004). "Interannual variability in upper ocean heat content, temperature, and thermosteric expansion on global scales". Journal of Geophysical Research 109. doi:10.1029/2003JC002260.
- Lyman, J. M.; Good, S. A.; Gouretski, V. V.; Ishii, M.; Johnson, G. C.; Palmer, M. D.; Smith, D. M.; Willis, J. K. (2010). "Robust warming of the global upper ocean". Nature 465 (7296): 334–337. doi:10.1038/nature09043. PMID 20485432.
- Syed, T. H.; Famiglietti, J. S.; Chambers, D. P.; Willis, J. K.; Hilburn, K. (2010). "Satellite-based global-ocean mass balance estimates of interannual variability and emerging trends in continental freshwater discharge". Proceedings of the National Academy of Sciences 107 (42): 17916. doi:10.1073/pnas.1003292107.
- "Josh K. Willis CV". JPL. Retrieved 7 September 2013.
- "Willis Receives 2011 Ocean Sciences Early Career Award". American Geophysical Union. 2011. Retrieved 7 September 2013.
- "Josh Willis". Jet Propulsion Laboratory website. Retrieved 7 September 2013.
- Buis, Alan (23 August 2011). "NASA Satellites Detect Pothole on Road to Higher Seas". Jet Propulsion Laboratory. Retrieved 7 September 2013.
- "Reddit Interview: Josh Willis". JPL. 17 October 2012. Retrieved 7 September 2013.
- Lyman, J. M.; Willis, J. K.; Johnson, G. C. (2006). "Recent cooling of the upper ocean". Geophysical Research Letters 33 (18). doi:10.1029/2006GL027033.
- Lindsey, Rebecca (5 November 2008). "Correcting Ocean Cooling". NASA Earth Observatory. Retrieved 7 September 2013.
- Revkin, Andrew C. (1 April 2008). "Ocean Cooling and Global Warming". New York Times. Retrieved 7 September 2013.
- Willis, J. K.; Lyman, J. M.; Johnson, G. C.; Gilson, J. (2007). "Correction to "Recent cooling of the upper ocean"". Geophysical Research Letters 34 (16): n/a. doi:10.1029/2007GL030323.
- Hobbs, W. R.; Willis, J. K. (2013). "Detection of an observed 135 year ocean temperature change from limited data". Geophysical Research Letters 40 (10): 2252. doi:10.1002/grl.50370.
- Nesbit, Jeff (31 May 2013). "Is More Global Warming Hiding in the Oceans?". Livescience.com. Retrieved 10 September 2013.
- "Century-old science helps confirm global warming". Institute for Marine and Antarctic Studies. Retrieved 10 September 2013.