ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Smoothing of Soil Wetness Index (SWI) in ALADIN/LACE domain Stjepan Ivatek-Šahdan Meteorological and Hydrological Service of Croatia

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th problem in LACE 2m Temperature forecasts during the June same problem in ARPEGE and ALADIN/FRANCE Problem: hot spots during the afternoon 2m TemperatureSWI

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th represents the hydric stress of the vegetation - SWI ≤ 0 - transpiration of the plants is zero (dry soils) - SWI ≥ 1 - vegetation evaporate at the maximal rate (wet soils) Definition: Smoothing of SWI (land points, without snow cower & ice in a ground) few checks Soil Wetness Index (SWI) - I

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Soil Wetness Index (SWI) - II Changes of SWI during the day There are no some important changes between analysis and forecasts!

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Smoothing of Soil Wetness Index (SWI) - I - smoothing: with data from 5-ALADIN 7-ARPEGE nearest grid points; - radius: 4.1 km (1/3 of grid size) or 6.1 km (1/2 of grid size); - number of smoothing: 10, 21 and 30; - XXSMRR: smoothing is performed XX times, radius RR*0.1 km; - 30SM smoothing with radius 6.1 km. winter

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Smoothing of Soil Wetness Index (SWI) - II SWI for 19 th June UTC - summer example

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Smoothing of Soil Wetness Index (SWI) - III

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results I - 12 days are chosen for testing: - 6 days in June 2002 and - 6 days in year 2003, 3 in January, 2 in April and 1 in May. - forecasts with ALADIN AL25T1_op2 in Croatia with different initial files For all Analyses no changes bigger than ±0.5 °C for T2m or ±2 % H2m. 3 days in January 2003 (07 th, 13 th and 16 th ) - 7 th - lot of snow in Croatia and precipitation in South Europe, max T2m around 0°C; - 13 th and 14 th - max T2m around 0°C, some sunny periods; - 16 th and 17 th - lot of sunshine, without rain for continental Europe, max T2m > 0°C. T2m: more than 600 points changes max 5 points bigger than 0.5 °C for each forecast. H2m: more than 600 points changes max 40 points bigger than 5 % for each forecast. There is no important impact for January. 1 st spring example, 2 nd and 5 th April nd and 3 rd - moving cyclone with frontal system over the Europe; - 2 nd sunny in Central and East Europe; - amplitude of T2m in continental Croatia 2 nd ~20 °C, 3 rd - west Croatia < 5 °C. - 5 th and 6 th West Europe no precipitation.T2m amplitude > 10 °C in South Europe.

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th T2m less than 5 % p. changes > ±0.5 °C, just 1 % > 2 °C; - H2m max. 20 % p. changed > ±2 %, few times H2m changed > 10 %. The Change is greater than for winter but not very big. Experiments and some results II 2 nd spring example, 6 th May th and 7 th May, front moving over West Europe, and than stop on Alps, other parts of Europe T2m amplitude ~ 20 °C, lot of sunshine. Hot spots over a Central Europe, smaller for 7 th. - T2m max. 22 % p. changed > ±0.5 °C, and 2 % > ±2 °C ; - H2m max. 45 % p. changed > H2m ±2 %, and 9 % > ±10 %. For this period impact of smoothing of SWI is relatively big.

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Results for problematic period in June period from June 15 th - 21 st very hot period T2m in Central Europe > 30 °C, with extreme values from the beginning of measuring. Very hot period for West Europe too, but not during the whole period. Generally when the number of smoothing or radius of smoothing are increased, values in more and more points change for more than ±0.5 °C or ±2 %, for forecasts. - T2m maximum 53 % p. changed > ±0.5 °C, and 9 % > ±2 °C; - H2m maximum 65 % p. changed > ±2 %, and 17 % > ±10 %. In this period, maximum changes of H2m and T2m were noticed in all examples. In summer examples, in areas with big gradients of surface temperature improvement in T2m forecast is really big, in same points for more than 2 °C, for radius of smoothing 6.1 km and for 21 or 30 times of smoothing, for 12 and 36 hrs forecast. Experiments and some results III

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results IV

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results V If the points are dark yellow, orange or red smoothing forecast is better. If the points are green, light or dark blue operational forecast is better. Comparison of results against SYNOP data comparison of absolute errors for T2m

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results VI

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results VII RMS and Bias for T2m For June 2002 T2m RMS is usually better for smoothed SWI, the differences are higher for 12, 36 and 18 hrs forecast, maximum for RMS=0.33 °C. BIAS is usually less than zero. Operational run is better for BIAS and difference is higher for 12, 18, 36 and 42 hrs forecasts. Maximum difference for BIAS=0.37 °C.

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results VIII If the points are dark yellow, orange or red smoothing forecast is better. If the points are green, light or dark blue operational forecast is better. Comparison of results against SYNOP data comparison of absolute errors for H2m

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Experiments and some results IX RMS and Bias for H2m For June 2002, with very high temperatures, RMS is better for runs with smoothed SWI, maximum improvement of RMS for H2m is For H2m BIAS operational forecast is often better than run with smoothed SWI, maximum difference for BIAS=0.024.

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Statistics for June 2002 against oper - “+++”- big improvement of forecast (greater than 2 °C or 5 %) ; - “++”- improvement (1-2 °C or 2-5 %) and; - “+” - small improvement in forecast (0.5-1 °C or %). - Same is for “-” classes, but for worse forecasts. Number in table > 0 more points with better forecast. “1*+++1*++1*+1*-1*--1*---” same weight for all classes2 nd weight is; “2*+++1.5*++1*+1*-2*--3*---” weight for worst forecast is little bit bigger; “2*+++1.5*++1*+1*-3*--4*---” bigger weight for worst forecast. Comparison of number of points with better and worse scores of operational run with smoothed runs, with different weights, for all days (15-20) and all forecasts (00, 06,…, 48)

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Statistics for June 2002 against 21SM61 smoothing Number of points with better and worse scores for T2m and H2m in comparison of 20SM61 with other runs (OPER and other smoothings: 10SM61, 21SM41, 30SM41 and 30SM61), sum for all forecasts hours: 00, 06, 12… 48 UTC, and for whole period, 15 th -20 th of June 2002 Comparison of number of points with better and worse scores for T2m of 20SM61 with 30SM61 smoothed run, with different weights, |err(21SM61)|-|err(30SM61)|, 15 th -20 th of June 2002

ALADIN/RC LACE Data Assimilation Mini-Workshop, Budapest, October 20 th -22 th Conclusion - during hot summer days, hot spots appear in T2m, caused by small scales features in the soil moisture, - problems in surface analysis and convective precipitation, - winter - small changes after smoothing; - summer - increasing number and radius of smoothing of SWI, SWI becomes smooth, maybe 30SM61 is to smooth, - with smoothed SWI - no more big gradients in T2m field, some points are colder for more than 2 °C, - January and April - no important changes in RMS and BIAS, - 15 th – 20 th June 2002 RMS is better for smoothed SWI, maximum improvement of RMS for H2m is 0.022, operational BIAS is better, maximum difference for BIAS= For T2m RMS is usually better for smoothed SWI, highest differences are for 12, 36 and 18 hrs forecast, maximum for RMS=0.334 °C. For all experiments BIAS is usually less than zero. Operational run better for BIAS and difference is higher for 12, 18, 36 and 42 hrs forecasts, maximum difference for BIAS=0.369 °C. -proposed solution: to use 21SM61 smoothing, smoothing applied 21 times and 6.1 km radius of smoothing (half of the horizontal grid), - test with longer parallel, - if the smoothing of SWI is used in ARPEGE it is not needed in ALADIN.