# Presentation: 796323

## A examination of MLS day/night temperature differences using NOGAPS-ALPHA 

*Presented by ****Karl Hoppel, ***
* *
**John McCormack, Larry Coy, Steve Eckermann, **
**Dave Siskind, Gerald Nedoluha**
*Naval Research Laboratory, Washington DC *
***M.J. Schwartz***
*Jet Propulsion Laboratory, Pasadena CA*

**A examination of MLS day/night temperature differences using NOGAPS-ALPHA **
**NWP assimilation system**

## Questions about MLS mesospheric temperatures

- (1) How do the day-night MLS mesospheric temperatures compare with other models and measurements?
-  Comparison with SABER temperatures
-  Comparison with GSWM (migrating diurnal & semidiurnal tides)‏
- (2) What happens to diurnal temperature variations when we assimilate MLS temperatures into a NWP model?
-  Examine migrating diurnal T during Jun-Jul 2007 from the NOGAPS-ALPHA analysis
-  Compare with 5-10 day forecasts (no data assimilation)

## NOGAPS-ALPHA/NAVDAS 3D-Var Assimilation Setup

-   6-Hour update cycles
-   Model resolution: T79L68
_**Standard Observations**_
-   Geostationary winds
-   AMSU-A radiances channels 4-10
-   MODIS AQUA & TERRA winds
-   QuickSCAT
-   Surface: land, ship, buoy, rawinsonde, profiler, pibal
-   Aircraft: MDCARS, AMDAR, etc.
_**New Observations**_
-   MLS v2 Temperature: 		  32 - 0.002 hPa
-   SABER v1.07 Temperature:    32 - 0.002 hPa
-   MLS v2 Ozone & H2O: 	  	300 - 0.002 hPa

**NOGAPS-ALPHA/NAVDAS 3D-Var Assimilation Setup**

*Hoppel et al., Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model, ACP 2008*
*Eckermann et al., High-Altitude Data Assimilation System Experiments for the Northern Summer Mesosphere Season of 2007, JASTP (in press)**‏*

**Notes:**
- 4-hour window for mls/saber in order to minimize errors due tides.

- T79 gives a horizontal resolution of 1.5 x 1.5 degrees.

- I've been assimilating the same 2 months for nearly 2 years!

- The higher AMSU-A channels are not used because they overlap with the MLS data – and I have not worked on a bias corrections for these two data sources

- There are other observations, such as AIRS hand HIRS that are being tested by NRL-MRY, but I am not using them at this time.

- The last group are the data I have been testing.  Temperatures from a bout 25km to 80km. 

*  I am going to show results of the MLS and SABER Temperature assimilations, and say little about the  Ozone and H2O assimilation.

## Measurement coverage for 6-hour cycle

-  Example of MLS (squares) and SABER (crosses) locations during 6-hours
-  Color shading shows the analysis increment (analysis-background) temperature correction (K) at 0.04 hPa.

**Measurement coverage for 6-hour cycle**

## Global Scale Wave Model (used for comparisons)‏

**http://www.hao.ucar.edu/modeling/gswm/gswm.html**

**Global Scale Wave Model (used for comparisons)****‏**

## GSWM and MLS for Jun-Jul 2007, 3oS-3oN

## MLS day & night time series, 5oS-5oN

*Note: ~9 km vertical smoothing applied to saber profiles*

## MLS day & night time series, 30oN-40oN

*Note: ~9 km vertical smoothing applied to saber profiles*

## MLS day & night time series, 40oN-50oN

*Note: ~9 km vertical smoothing applied to saber profiles*

## Local time variation for Jun-Jul 2007, 3oS-3oN

## Local time variation for Jun-Jul 2007, 3oS-3oN

## Local time variation for Jun-Jul 2007, 3oS-3oN

## Local time variation for Jun-Jul 2007, 3oS-3oN

## Local time variation for Jun-Jul 2007, 20oN-26oN

## Local time variation for Jun-Jul 2007, 40oN-46oN

## Conclusions

-   The MLS day-night temperature at ~0.01 - 0.0046 hPa in northern mid-latitude summer is unusually large;T(day)>>T(night).
-   The corresponding southern mid-latitude summer day-night is unusually small, T(night)>T(day), compared with SABER and GSWM (not shown in presentation).
-   Lower in the mesosphere, 0.2 - .014 hPa, mid-latitude day-night values decrease in magnitude, and exhibit increased interannual variation.  Discrepancies between MLS and SABER day-night are found, but it is more difficult to identify systematic biases.
-   Equatorial SABER and MLS day-night values are similar throughout the mesosphere

## END

- (Backup slides follow)‏

## New Physics, Dynamics & Chemistry for the Mesosphere & Lower Thermosphere (MLT)‏

-  Longwave radiation extended to *p*<0.01hPa using Fomichev parameterization of **non-LTE CO****2**** cooling**
-  **near-IR CO****2**** heating** corrected for non-LTE
-  Fully **prognostic ozone and water vapor**
-  3D initialization & spectral advection
-  Linearized odd-oxygen and water vapor photochemistry schemes (former transitioned to NCEP GFS August 2006)‏
-  Prognostic ozone and water feed into radiation to modify radiative heating/cooling (fully interactive)‏
-  “Cold tracer” for PSC (or PMC) formation and heterogeneous ozone loss
-  **prognostic CH****4**** and N****2****O** capabilities added, via initialization, advection & parameterized chemistry
-  new MLT parameterizations of **nonorographic gravity wave drag and diffusion**
-  and _many_ other additions too.....

**New Physics, Dynamics & Chemistry for the Mesosphere & Lower Thermosphere (MLT)****‏**

## MLS day & night time series, 10oN-20oN

*Note: ~9 km vertical smoothing applied to saber profiles*

## MLS day & night time series, 40oS-30oS

*Note: ~9 km vertical smoothing applied to saber profiles*

## Local time variation for Jun-Jul 2007, 60oN-66oN

## Example of zonal-mean temperature from NOGAPS-ALPHA assimilation of MLS and SABER data

**Example of zonal-mean temperature from NOGAPS-ALPHA assimilation of MLS and SABER data**

**Temperature analysis from NOGAPS-ALPHA using MLS and SABER**

## Global O-F (innovation) Averages, Jun-Aug 2007

**Global O-F (innovation) Averages, Jun-Aug 2007**

**MLS **
**SABER**

-  Average O-F less then ~1 K (**good**)
-  MLS & SABER O-F differ by < ~2K (*okay*)
-  A single bias correction profile was applied to MLS data globally based on published validation results.

## O-F Averages for MLS day & night temperatures

**O-F Averages for MLS day & night temperatures**

**MLS Day**
**MLS Night**

- Huge day-night O-F
- differences in the mesosphere at some latitudes

## Global O-F (innovation) Statistics

**Global O-F (innovation) Statistics**

**MLS **
**SABER**

## Background: 3D-Var Data Assimilation

**H****(x****f****) - nonlinear mapping of forecast into observation space.  H is linearized operator**

**Error assumptions (P,R)****‏**

**Model forecast**
**“****background” (x****f****)****‏**

**Observations (y)****‏**

**Length of state vector: 10****7**** – 10****8                                    ****Number of obs: 10****6 **

**Notes:**
The main challenge is the dimension of the problem, and this makes it difficult to solve.
Number of observations is order of 10**6 and the number of grid points is order of 10**8. Underdetermined.
Innovation is the new information coming from the ob, and is the difference between the observation and the model background mapped into obs space.

## Local time variation for Jun-Jul 2007, 51oN-57oN

**SHIMMER PMC **
**observation frequency*10**
**for 2007, from Stevens et al.,**
**JASTP (in press)****‏**