1. Tropospheric Emissions: Monitoring of Pollution Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 1 TEMPO Instrument Performance TEMPO Science Team Meeting July 23-24 2013

2. Tropospheric Emissions: Monitoring of Pollution 2 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 Outline Notional TEMPO instrument layout Instrument parameter assumptions Instrument EOL SNR performance EOL SNR impacts of a colder detector Closing remarks Introduction

3. Tropospheric Emissions: Monitoring of Pollution 3 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 Notional TEMPO Instrument Layout Notional Layout Instrument trades are on-going to minimize instrument packaging while maximizing instrument performance

4. Tropospheric Emissions: Monitoring of Pollution 4 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 Instrument Parameters ParameterValueComment Frame Integration Time160 msSet by saturation requirement Coadded Frames16Set by SNR and Coverage Time Requirement Spectral Range290-485nm, 535-750nmUtilizes two CCDs Spectral Dispersion0.21 nm/pixelAssumes 2048 pixels for spectral coverage – best case assumption Spectral Sampling2.84 samples / FWHMDictated by slit width and pixel pitch (to first order) Spectral Bandpass0.596 nmDictated by slit width, dispersion, and pixel pitch (to first order) Detector Full Well300 ke-CCD designers are indicating that 200 ke- is more realistic; reduction will have performance implications Detector Operating Temperature +5 deg CDark current and Random Telegraph Noise levels do not drive SNR performance N/S GSD8 kmSpatially binning four 2 km N/S pixels E/W GSD4.2 kmDictated by spectrometer slit width and N/S GSD Coverage Time60 minutesMeets requirement value of 60 minutes Parameters

5. Tropospheric Emissions: Monitoring of Pollution 5 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 EOL SNR Performance Snapshot Requirements shown are from Xiong Liu (July 18, 2013) EOL SNR

6. Tropospheric Emissions: Monitoring of Pollution 6 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 O3 Channels Have Insufficient Margin Atmospheric Constituent Wvl (nm) SNR Reqmt SNR Perf +5° C Margin +5° C O32902730 11% O33005966 11% O3, SO2305204224 10% O3, SO2310480526 10% O3, SO232015161654 9% O3, H2CO, SO233023692583 9% O3, H2CO, Cloud34023542567 9% H2CO, Cloud, AOD35014142405 70% AOD38014142200 56% NO24207692623 241% NO2, C2H2O243018302280 25% C2H2O246021232646 25% Cloud49017002350 38% O354017541913 9% O360015741717 9% O365014641597 9% Cloud, Aerosols6908881308 47% EOL SNR Performance BATC SE guidelines recommend at least 30% SNR margin at SRR Several channels do not meet the minimum SNR margin guideline of 30%

7. Tropospheric Emissions: Monitoring of Pollution 7 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 O3 Channels Have Insufficient Margin Atmospheric Constituent Wvl (nm) SNR Reqmt SNR Perf +5° C Margin +5° C SNR Perf -15° C Margin -15° C O32902730 11% 4876% O33005966 11% 10068% O3, SO2305204224 10% 29746% O3, SO2310480526 10% 61227% O3, SO232015161654 9% 170813% O3, H2CO, SO233023692583 9% 262111% O3, H2CO, Cloud34023542567 9% 260511% H2CO, Cloud, AOD35014142405 70% 244673% AOD38014142200 56% 224359% NO24207692623 241% 2660246% NO2, C2H2O243018302280 25% 232227% C2H2O246021232646 25% 268326% Cloud49017002350 38% 239141% O354017541913 9% 196212% O360015741717 9% 177012% O365014641597 9% 165313% Cloud, Aerosols6908881308 47% 137254% EOL SNR Performance Detector dark current at -15° C is reduced by a factor of approximately 10 compared to +5° C Cooling detectors to -15° C gives more margin, but only pushes three channels above the 30% margin guideline There are not many instrument parameters that can be adjusted to give the 30% SNR margin at the O3 channels –30% margin may require unrealistically high optical throughput, for example

8. Tropospheric Emissions: Monitoring of Pollution 8 Use or disclosure of this information may be subject to United States export control laws. For official use only. 23 July 2013 Closing Remarks Design work for TEMPO is on-going Finalization of spectral range, SNR, GSD and Field of Regard requirements will facilitate design activities Several channels drive the system in terms of SNR performance –Colder detector temperatures give some relief in the UV, but signal shot noise and other noise terms dominate the SNR in the VIS »Artificially setting the dark current equal to zero does not result in significantly more SNR margin for those driving channels Updated instrument parameters will impact SNR performance –Detector design indicates that the full well will decrease »This will require shorter integration times and more coadds –Detector designers indicate the QE will increase »This will help in terms of signal collection in the UV, but may require further shortening of the integration time and increase of coadds –Taking a closer look at optical throughputs, etc… BATC looks forward to contract award and continued fruitful discussions with the TEMPO science team Summary