Comparison of maritime measurements of <i>C</i><i>n</i>2 with NAVSLaM model predictions
Rita Mahon, Christopher I. Moore, Mike S. Ferraro, William S. Rabinovich, Paul A. Frederickson
Abstract
In this paper, a study is made of the refractive index structure parameter <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>C</mml:mi> </mml:mrow> <mml:mi>n</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> , as derived from angle-of-arrival (AOA) measurements made on the beam after propagation along a 16 km slant path across the Chesapeake Bay. These measurements are compared with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>C</mml:mi> </mml:mrow> <mml:mi>n</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> estimates derived from the Navy Atmospheric Vertical Surface Layer Model (NAVSLaM), which are based upon prevailing meteorological conditions. Correlation coefficients for the reported data vary between 0.64 and 0.9. Despite the Chesapeake Bay theoretically being a difficult location for employing a Monin–Obukhov similarity theory-based model such as NAVSLaM, the agreement between the AOA <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>C</mml:mi> </mml:mrow> <mml:mi>n</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> measurements and the NAVSLaM <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>C</mml:mi> </mml:mrow> <mml:mi>n</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> estimates was, in many cases, good. A possible explanation of this agreement between the modeled and measured <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>C</mml:mi> </mml:mrow> <mml:mi>n</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> values is that the large air–water temperature differences encountered provided such strong forcing for the NAVSLaM model that any potential violations of the Monin–Obukhov similarity theory assumptions had only a secondary influence on the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>C</mml:mi> </mml:mrow> <mml:mi>n</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> estimates.