weather derivatives in general, however, are
inherently incomplete since weather is not a tradable asset and hence it is impossible
to construct a riskless hedge portfolio containing the weather derivative. In turn, it is
impossible to find a unique risk-neutral measure Q, i.e. a martingale measure equivalent
to the physical measure P. Instead, many equivalent martingales exist and as a result,
only bounds for prices on contingent claims can be provided on the basis of no-arbitrage
arguments (Jensen and Nielsen, 1996, pp. 221–2, Benth, 2004, p. 88). We specify a class
of probability measures using the Esscher transform, which will provide us with the MPR
parametrized by .