Hydrologic Abstractions in Rainfall-Runoff Relationships:

• Definitions:
• Total Rainfall Hyetograph: Plot of gross rainfall intensity or depth against time.
• Effective / Excess Rainfall Hyetograph (ERH): That portion of rainfall that becomes direct surface runoff.
• Hydrological Abstractions: The difference between total rainfall and effective rainfall represents the total hydrological abstraction (losses):
  $$\text{Abstraction} = \text{Total Rainfall} - \text{Excess Rainfall}$$
  Abstractions comprise interception by vegetation, surface depression storage, evaporation, and infiltration into the soil profile.

Calculation of Recurrence Interval using Weibull Plotting Position:

• Formula: According to the Weibull formula, the return period / recurrence interval ($T$) for an event of rank $m$ in a record length of $N$ years is:
  $$T = \frac{N + 1}{m}$$
• Given Data:
• Total years of record ($N$) = $16$
• Rank of the event ($m$) = $10$
• Calculation:
  $$T = \frac{16 + 1}{10} = \frac{17}{10} = 1.7\text{ years}$$
  (Note: Probability of exceedance $P = m / (N+1) = 10 / 17 = 0.588$).

Atmospheric Dynamics of Cyclones and Anticyclones:

• Statement (A) is Correct: An anticyclone is a weather system with high atmospheric pressure at its center around which air circulates clockwise in the Northern Hemisphere (due to the Coriolis deflection to the right) and counter-clockwise in the Southern Hemisphere.
• Statement (B) is Incorrect: Anticyclones are high-pressure systems, not low-pressure systems.
• Statement (C) is Correct: A cyclone is an intense low-pressure system surrounded by closed isobars with counter-clockwise inward circular wind motion in the Northern Hemisphere.