1. Theo Brandsma KNMI, the Netherlands International workshop on the digitization of historical climate data the new SACA&D databases and climate analysis in the Asian region Citeko, Bogor, Indonesia, 2-5 April 2012 Daily Indonesian rainfall in the 1879–1916 period

2. 2 1.Obtaining knowledge of the rainfall climate in Indonesia 2.Design of irrigation systems 3.Planning of agricultural crops 4.Planning of infrastructural works like railways Reasons for setting op a rainfall network Background

3. 3 Growth of the network

4. 4 Number of stations with daily rainfall (1879-1916)

5. 5 Distribution of the stations in 1879 (124 stations) Growth of the network

6. 6 Distribution of the stations in 1900 (225 stations) Growth of the network

7. 7 Standardization

8. 8 Rain gauge 1.Rim at 1.2 m above ground level 2.Diameter of 12 cm 3.Vessel containing 275 mm

9. 9 Standardization Regulation examples 1.Following the orders of the director of the Batavia observatory concerning the positioning of the rain gauge 2.Measuring of rainfall each morning at 6, 7, 8, or 9 local time and assigning it to the day of measurement on specially prepared measurement forms 3.Rounding the measurements to whole mm 4.Sending two duplicates of the daily measurements to Batavia/Jakarta right after the end of a month by two subsequent postal deliveries (and keeping the original for another six months) 5.Publishing monthly summaries in the Javasche Courant en the daily values in the annual rainfall books (by the director)

10. 10 Digitization and quality control

11. 11 Digitization and quality control Example from the yearbooks 1.Scanning 2.OCR 3.Quality control 4.Database

12. 12 ― means no rain n.w. means not measured * means multi-day amount †means measuring period not exactly 24 hours w.o. means incomplete measurement, monthly totals could not be calculated Possible codes Digitization and quality control

13. 13 Digitization and quality control Example page

14. 14 Final goal: to import the 1879-1916 daily rainfall series in SACA&D Digitization and quality control

15. 15 1.Extreme-value analysis 2.Studies of climate change and variability 3.Validation of climate models Possible applications of the dataset Applications

16. 16 Terima Kasih