GRB 100816***A***, Swift-BAT refined analysis S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+843 sec from the recent telemetry downlink, we report further analysis of BAT GRB 100816***A*** (trigger #431764) (NAME, et al., GCN Circ. xxxx). The BAT ground-calculated position is RA, Dec = 351.738, 26.568 deg which is RA(J2000) = 23h 26m 57.1s Dec(J2000) = +26d 34' 04.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%. [Description about the mask-weighted light curve] T90 (15-350 keV) is 2.9 +- 0.6 sec (estimated error including systematics). The time-averaged spectrum from T-0.7 to T+4.5 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.74 +- 0.24, and Epeak of 172.2 +- 82.4 keV (chi squared 50.40 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.9 +- 0.1 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+0.10 sec in the 15-150 keV band is 11.0 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.17 +- 0.06 (chi squared 61.05 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/431764/BA/