REPORT ABOUT ENVISAT SCIAMACHY NRT OZONE PRODUCT (SCI RV 2P) FOR JULY August 11, 2005

Transcription

1 REPORT ABOUT ENVISAT SCIAMACHY NRT OZONE PRODUCT (SCI RV 2P) Vanda da Costa Bechtold ECMWF, Shinfield Park, Reading, RG2 9AX, United Kingdom, Tel: August, 5. Key points for July 5 SCIAMACHY data quality stable. SCIAMACHY data about 5 DU lower in the global mean than ECMWF ozone values. Slight increase of the (negative) global mean departures (SCIAMACHY-ECMWF) from 28 July onwards. No data on 4 July ( UTC) and July (6, 2, 8 UTC). 2. Quality and amount of received data This report covers SCIAMACHY NRT total column ozone data for July 5. Amount of received data and their quality are shown in Figures -6 for various latitude bands. Geographical distributions of mean number of data, mean observation values and mean first-guess departures are shown in Figures 7-9. Timeseries of zonal mean number of data, zonal mean observation values and zonal mean first-guess departures are shown in Figures -2. Figures 3-5 present the scatter plots of SCIAMACHY ozone values against first-guess and latitude values, as well as the scatter plot of first-guess departures of SCIAMACHY ozone values against latitude. The timeseries plots (Figures -6) show that SCIAMACHY data quality is stable in July. The global mean departures (SCIAMACHY-ECMWF) are around -5 DU, however slightly larger global mean negative biases can be seen after 28 July until the end of the month. The standard deviations of the model departures have also been stable in July. Regarding the SCIA- MACHY data standard deviations, the decrease observed from April to the end of June is not noticeable anymore. In the global mean the standard deviations of the model departures are around 5 DU, whereas the standard deviations of the SCIAMACHY data are roughly around 3 DU. There are no data on 4 July ( UTC) and July (6, 2 and 8 UTC). The geo plots, the hovmoeller plots and the scatter plots (Figures 7-5) show that the largest biases are observed at the southern high latitudes. These large mean departures are likely to occur at high solar zenith angles.

2 3. Remarks This monitoring report was produced with the operational ECMWF model (CY29R2). In cycle CY29R2 ozone layers from SBUV/2 on NOAA-6 and SCIAMACHY total column ozone data produced by KNMI are actively assimilated. The comparison of SCI RV 2P data against the ECMWF ozone field does not give an independent validation. All ozone values are in Dobson Units (DU). 2

3 Number Statistics for Ozone from ENVISAT / SCIAMACHY Layer =, hpa, All Data Area: lon_w=., lon_e= 3., lat_n= 9., lat_s= -9. (all surface types) EXP =, Data Period = OBS FG ANA OBS-FG OBS-AN stdv(obs-fg) stdv(obs-an) stdv(obs) n_displayed n_all n_active n_used n_not_active Fig.. Time series of mean observations, first guess and analysis values (top panel), first-guess and analysis departures (second panel), standard deviations (third panel) and number of data (bottom panel) per 6-hour cycle for ENVISAT SCIAMACHY NRT ozone data for July 5 (Global means). 3

4 Number Statistics for Ozone from ENVISAT / SCIAMACHY Layer =, hpa, All Data Area: lon_w=., lon_e= 3., lat_n= 9., lat_s=. (all surface types) EXP =, Data Period = OBS FG ANA OBS-FG OBS-AN stdv(obs-fg) stdv(obs-an) stdv(obs) n_displayed n_all n_active n_used n_not_active Fig. 2. As Fig. but for 9-N. 4

5 Number Statistics for Ozone from ENVISAT / SCIAMACHY Layer =, hpa, All Data Area: lon_w=., lon_e= 3., lat_n=., lat_s= 3. (all surface types) EXP =, Data Period = OBS FG ANA OBS-FG OBS-AN stdv(obs-fg) stdv(obs-an) stdv(obs) n_displayed n_all n_active n_used n_not_active Fig. 3. As Fig. but for -3N. 5

6 Number Statistics for Ozone from ENVISAT / SCIAMACHY Layer =, hpa, All Data Area: lon_w=., lon_e= 3., lat_n= 3., lat_s= -3. (all surface types) EXP =, Data Period = OBS FG ANA OBS-FG OBS-AN stdv(obs-fg) stdv(obs-an) stdv(obs) n_displayed n_all n_active n_used n_not_active Fig. 4. As Fig. but for 3N-3S. 6

7 Number Statistics for Ozone from ENVISAT / SCIAMACHY Layer =, hpa, All Data Area: lon_w=., lon_e= 3., lat_n= -3., lat_s= -. (all surface types) EXP =, Data Period = OBS FG ANA OBS-FG OBS-AN stdv(obs-fg) stdv(obs-an) stdv(obs) n_displayed n_all n_active n_used n_not_active Fig. 5. As Fig. but for 3-S. 7

8 Number Statistics for Ozone from ENVISAT / SCIAMACHY Layer =, hpa, All Data Area: lon_w=., lon_e= 3., lat_n= -., lat_s= -9. (all surface types) EXP =, Data Period = OBS FG ANA OBS-FG OBS-AN stdv(obs-fg) stdv(obs-an) stdv(obs) n_displayed n_all n_active n_used n_not_active Fig. 6. As Fig. but for -9S. 8

9 STATISTICS FOR OZONE FROM ENVISAT / SCIAMACHY NUMBER OF OBSERVATIONS PER GRID SQUARE (ALL) DATA PERIOD = EXP =, LAYER =, HPA Min: Max: 52 Mean: N 3 N 3 N 3 S 3 S S 5 W 5 W W W 9 W 9 W W W 3 W 3 W 3 E 3 E E E 9 E 9 E E E 5 E 5 E N S Fig. 7. Geographical distribution of mean number of data for ENVISAT SCIAMACHY NRT ozone data for July 5. STATISTICS FOR OZONE FROM ENVISAT / SCIAMACHY MEAN OBSERVATION [DU] (ALL) DATA PERIOD = EXP =, LAYER =, HPA Min: Max: 4.46 Mean: N 3 N 3 N 3 S 3 S S 5 W 5 W W W 9 W 9 W W W 3 W 3 W 3 E 3 E E E 9 E 9 E E E 5 E 5 E N S Fig. 8. Geographical distribution of mean observation values for ENVISAT SCIAMACHY NRT ozone data for July 5. 9

10 Latitude, STATISTICS FOR OZONE FROM ENVISAT / SCIAMACHY MEAN FIRST GUESS DEPARTURE (OBS-FG) [DU] (ALL) DATA PERIOD = EXP =, LAYER =, HPA Min: Max: Mean: N 3 N 3 N 3 S 3 S S 5 W 5 W W W 9 W 9 W W W 3 W 3 W 3 E 3 E E E 9 E 9 E E E 5 E 5 E N S Fig. 9. Geographical distribution of mean first-guess departures for ENVISAT SCIAMACHY NRT ozone data for July 5. STATISTICS FOR OZONE FROM ENVISAT / SCIAMACHY LAYER =, HPA NUMBER OF OBSERVATIONS IN AVERAGE (ALL) EXP =, DATA PERIOD = Min: Max: 9 Mean: ! " 2 # 3 $ 4 % 5 & 6 ' 7 ( 8 ) 9 * 2 " 3 # 4 $ 5 % 6 & 7 ' 8 ( 9 ) * 2 22 " 23 # 24 $ 25 % 26 & 27 ' 28 ( 29 ) 3 * 3 + ) 9 ( ' 7 & % 5 $ # 3 " * Fig.. Hovmoeller diagram of zonal mean number of data for ENVISAT SCIAMACHY NRT ozone data per 6-hour cycle for July 5.

11 Latitude Latitude < > < ; : 9 STATISTICS FOR OZONE FROM ENVISAT / SCIAMACHY LAYER =, HPA ZONAL MEAN OBSERVATION (ALL) EXP =, DATA PERIOD = Min: 23.7 Max:.6 Mean: / < 525 < ; 475 ; 45 ; 425 ; : 375 : 35 : 325 : Fig.. Hovmoeller diagram of zonal mean observation values for ENVISAT SCIAMACHY NRT ozone data per 6-hour cycle for July 5. STATISTICS FOR OZONE FROM ENVISAT / SCIAMACHY LAYER =, HPA ZONAL MEAN FIRST GUESS DEPARTURE (OBS-FG) (ALL) EXP =, DATA PERIOD = Min: Max: Mean: / = Fig. 2. Hovmoeller diagram of zonal mean first-guess departures for ENVISAT SCIAMACHY NRT ozone data per 6-hour cycle for July 5.

12 OBS OBS OBS-FG L K K Scatterplot of OBS versus FG SCIAMACHY on ENVISAT, total column EXP = ; Period = 57 to 5738 All Data B B B B B B B 7 B B 9 B FG Total number = Maximum number per bin = 8862 OBS min = 43.8 max = FG min = 24.8 max = 452. y mean = 292. y stdev = 3.3 x mean = x stdev = 3. BIAS (y-x) = -4.9 RMS = 6.2 corr. coef. =.872 Fig. 3. Scatter plot of ENVISAT SCIAMACHY ozone values against latitude for July 5. The colours show the number per bin, the black dots the mean values per bin. Scatterplot of Observations versus Latitude SCIAMACHY on ENVISAT, total column EXP = ; Period = 57 to 5738 All Data C - D -7 E - F -5 G - H -3 I - J - B Latitude [ deg ] Total number = Maximum number per bin = 98 OBS min = 43.8 max = Latitude min = max = 85. y mean = 292. y stdev = 3.3 Fig. 4. Scatter plot of ENVISAT SCIAMACHY ozone values against latitude for July 5. The colours show the number per bin, the black dots the mean values per bin. Scatterplot of FG Departures versus Latitude SCIAMACHY on ENVISAT, total column EXP = ; Period = 57 to 5738 All Data C - D -7 E - F -5 G - H -3 I - J - B Latitude [ deg ] Total number = Maximum number per bin = 2 OBS min = 43.8 max = FG min = 24.8 max = 452. Latitude min = max = 85. y mean = -4.9 y stdev = 5.4 Fig. 5. Scatter plot of first-guess departures of ENVISAT SCIAMACHY ozone against latitude for July 5. The colours show the number per bin, the black dots the mean values per bin. 2