function gfsDate(attr) {
        if (attr.date === "current") {
            // Construct the date from the current time, rounding down to the nearest three-hour block.
            var now = new Date(Date.now()), hour = Math.floor(now.getUTCHours() / 3);
            return new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate(), hour));
        }
        var parts = attr.date.split("/");
        return new Date(Date.UTC(+parts[0], parts[1] - 1, +parts[2], +attr.hour.substr(0, 2)));
    }
@param attr
@param {String} type
@param {String?} surface
@param {String?} level
@returns {String}