CCM EXAM QUESTION 1

OVERVIEW• A construction worker has building plans in the San Gabriel Mountains. Erosion is a big

issue since access roads will not be paved and vegetation won’t be able to stabilize soils.

• A news report stated that west coast precipitation anomalies are directly significantly related to Pacific indices.

• He is interested in the relation between PDO indices and Southern California rainfall because the news report stated that PDO was expected to be negative over the next 5 years, and therefore rainfall was expected to be minimal.

• Hired a consulting meteorologist to determine if the news report was correct and to discuss their personal views on the issues with respect to his construction plans.

PART 1: NEWS REPORT • For PDO: for 56 years, the correlation coefficient of 0.104 gave a significance level of

0.4916. This is NOT statistically significant.

• Does not necessarily mean that when PDO is negative, there will not be rainfall in Southern California.

• Not a good predictor of precipitation.

PART 1 CONTINUED• For Nino3: for 56 years, the correlation coefficient of 0.55 gave a significance level of

0.01. This is statistically significant.

• Nino3 is a much better predictor of precipitation in Southern California.

• The news report, which downplays El Nino’s impact on precipitation is incorrect.

PART 2: MY VIEWS• Disregard the news report. It is confusing to the reader.

• There are wide variations in rainfall in Southern California.

• Expect some erosion. Perhaps build a barrier around the site and access roads.

• SOI is a good indicator of predicted rainfall. It has a correlation coefficient of -0.55 which gave a significance level of 0.01.

• Work as much as possible during the summer drought.