ContourPlot[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2},
ColorFunction -> ColorData[{"TemperatureMap", {0, 1}}]]
ContourPlot[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2},
ColorFunction -> ColorData[{"TemperatureMap", "Reverse"}]]

ContourPlot[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2},
ColorFunction -> ColorData[{"TemperatureMap", "Reverse", {1, 0}}]]

ColorData::notent: {TemperatureMap, Reverse, {1, 0}} is not a known entity,
class, or tag for ColorData. Use ColorData[] for a list of entities."