Mesospheric temperature sensing lidar apparatus

A system for measuring temperatures at respective altitudes of a middle atmosphere, said system comprising,

• a laser for generating two pulses respectively at two wavelengths exciting material in said middle atmosphere, said middle atmosphere respectively backscattering two returns, said material comprises atomic iron, said two returns respectively comprise two elastic returns and respectively comprise two fluorescence resonance line returns,
• an optical transmitter for transmitting said two pulses into said middle atmosphere, said two wavelengths and said two returns are at 371.99 nm and 373.71 nm,
• an optical receiver for collecting said two returns being backscattered from said middle atmosphere,
• an optical filter for passing said two returns and filtering background noise,
• a photodetector for converting said two returns into electronic counts, and
• a data processor for implementing a Boltzmann technique and a Rayleigh technique for relating said electronic counts to said temperatures, said Boltzmann technique for measuring temperatures of said atomic iron in a higher portion of said middle atmosphere by relating said temperatures to ratios of said two fluorescence resonance line returns, and said Rayleigh technique for measuring said temperatures in a lower portion of said middle atmosphere by relating at least one of said two elastic returns to said temperatures.

A method for measuring temperatures at respective altitudes of a middle atmosphere, said method comprising the steps of,

• generating first pulses at a first wavelength,
• transmitting said first pulses for a predetermined amount of first transmission time period into said middle atmosphere, said middle atmosphere backscattering said first pulses into first returns comprising first fluorescence resonance line returns,
• collecting said first returns for said first wavelength for a predetermined amount of first collection time period,
• filtering said first returns for passing said first returns and filtering background noise,
• converting said first returns into first electronic counts,
• storing said first electronic counts,
• generating second pulses at a second wavelength,
• transmitting said second pulses for a predetermined amount of second transmission time period into said middle atmosphere, said middle atmosphere backscattering said second pulses into second returns comprising second fluorescence resonance line returns,
• collecting said second returns for said second wavelength for a predetermined amount of second collection time period,
• filtering said second returns for passing said second returns and filtering background noise,
• converting said second returns into second electronic counts,
• storing said second electronic counts, and
• computing said temperatures of said middle atmosphere using a Boltzmann technique based on said first and second fluorescence resonance line returns by relating ratios of said first and second electronic counts to said temperatures.

A method for measuring temperatures at respective altitudes of a middle atmosphere having an upper altitude, a middle altitude and a bottom altitude, said method comprising the steps of,

• generating first pulses at a first wavelength,
• transmitting said first pulses for a predetermined amount of first transmission time period into said middle atmosphere, said middle atmosphere backscattering said first pulses into first returns comprising first fluorescence resonance line returns and first elastic returns,
• collecting said first returns for said first wavelength for a predetermined amount of first collection time period,
• filtering said first returns for passing said first returns and filtering background noise,
• converting said first returns into first electronic counts,
• storing said first electronic counts,
• generating second pulses at a second wavelength,
• transmitting said second pulses for a predetermined amount of second transmission time period into said middle atmosphere, said middle atmosphere backscattering said second pulses into second returns comprising second fluorescence resonance line returns and second elastic returns,
• collecting said second returns for said second wavelength for a predetermined amount of second collection time period,
• filtering said second returns for passing said second returns and filtering background noise,
• converting said second returns into second electronic counts,
• storing said second electronic counts, and
• computing temperatures of said middle atmosphere between said upper altitude and said middle altitude using a Boltzmann technique based on said first and second fluorescence resonance line returns by relating said first and second electronic counts to said temperatures between said upper altitude and said middle altitude of said middle atmosphere, and
• computing temperatures of said middle atmosphere between said middle altitude and said bottom altitude using a Rayleigh technique based on said first and second elastic returns by relating one of said first and second electronic counts to said temperatures between said middle altitude and said bottom altitude of said middle atmosphere.